When checking for pcap_if_t, add $V_INCLS to CFLAGS, so we look at the

[tcpdump] / tcpdump.1

diff --git a/tcpdump.1 b/tcpdump.1
index 7170a935e8040e423d00162d539a82f397b088f0..5f55299fecf12ba48083c53ed36b4169a56bcc4a 100644 (file)
--- a/tcpdump.1
+++ b/tcpdump.1
@@ -1,4 +1,6 @@
-.\" @(#) $Header: /tcpdump/master/tcpdump/Attic/tcpdump.1,v 1.71 1999-12-13 18:06:15 mcr Exp $ (LBL)
+.\" @(#) $Header: /tcpdump/master/tcpdump/Attic/tcpdump.1,v 1.163 2004-06-12 08:51:23 guy Exp $ (LBL)
+.\"
+.\"    $NetBSD: tcpdump.8,v 1.9 2003/03/31 00:18:17 perry Exp $

 .\"
 .\" Copyright (c) 1987, 1988, 1989, 1990, 1991, 1992, 1994, 1995, 1996, 1997
 .\"    The Regents of the University of California.  All rights reserved.
 .\"
 .\" Copyright (c) 1987, 1988, 1989, 1990, 1991, 1992, 1994, 1995, 1996, 1997
 .\"    The Regents of the University of California.  All rights reserved.


@@ -20,17 +22,23 @@
 .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 .\"
 .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 .\"

-.TH TCPDUMP 1  "30 June 1997"
+.TH TCPDUMP 1  "22 March 2004"

 .SH NAME
 tcpdump \- dump traffic on a network
 .SH SYNOPSIS
 .na
 .B tcpdump
 [
 .SH NAME
 tcpdump \- dump traffic on a network
 .SH SYNOPSIS
 .na
 .B tcpdump
 [

-.B \-adeflnNOpqRStvx
+.B \-AdDeflLnNOpqRStuUvxX

 ] [
 .B \-c
 .I count
 ] [
 .B \-c
 .I count

+]
+.br
+.ti +8
+[
+.B \-C
+.I file_size

 ] [
 .B \-F
 .I file
 ] [
 .B \-F
 .I file


@@ -46,12 +54,16 @@ tcpdump \- dump traffic on a network
 .I module
 ]
 [
 .I module
 ]
 [

-.B \-r
-.I file
+.B \-M
+.I secret

 ]
 .br
 .ti +8
 [
 ]
 .br
 .ti +8
 [

+.B \-r
+.I file
+]
+[

 .B \-s
 .I snaplen
 ]
 .B \-s
 .I snaplen
 ]


@@ -66,6 +78,27 @@ tcpdump \- dump traffic on a network
 .br
 .ti +8
 [
 .br
 .ti +8
 [

+.B \-W
+.I filecount
+]
+.br
+.ti +8
+[
+.B \-E
+.I spi@ipaddr algo:secret,...
+]
+.br
+.ti +8
+[
+.B \-y
+.I datalinktype
+]
+[
+.B \-Z
+.I user
+]
+.ti +8
+[

 .I expression
 ]
 .br
 .I expression
 ]
 .br


@@ -73,40 +106,161 @@ tcpdump \- dump traffic on a network
 .SH DESCRIPTION
 .LP
 \fITcpdump\fP prints out the headers of packets on a network interface
 .SH DESCRIPTION
 .LP
 \fITcpdump\fP prints out the headers of packets on a network interface

-that match the boolean \fIexpression\fP.
+that match the boolean \fIexpression\fP.  It can also be run with the
+.B \-w
+flag, which causes it to save the packet data to a file for later
+analysis, and/or with the
+.B \-r
+flag, which causes it to read from a saved packet file rather than to
+read packets from a network interface.  In all cases, only packets that
+match
+.I expression
+will be processed by
+.IR tcpdump .

 .LP
 .LP

-.B Under SunOS with nit or bpf:
-To run
+.I Tcpdump
+will, if not run with the
+.B \-c
+flag, continue capturing packets until it is interrupted by a SIGINT
+signal (generated, for example, by typing your interrupt character,
+typically control-C) or a SIGTERM signal (typically generated with the
+.BR kill (1)
+command); if run with the
+.B \-c
+flag, it will capture packets until it is interrupted by a SIGINT or
+SIGTERM signal or the specified number of packets have been processed.
+.LP
+When
+.I tcpdump
+finishes capturing packets, it will report counts of:
+.IP
+packets ``captured'' (this is the number of packets that
+.I tcpdump
+has received and processed);
+.IP
+packets ``received by filter'' (the meaning of this depends on the OS on
+which you're running
+.IR tcpdump ,
+and possibly on the way the OS was configured - if a filter was
+specified on the command line, on some OSes it counts packets regardless
+of whether they were matched by the filter expression and, even if they
+were matched by the filter expression, regardless of whether
+.I tcpdump
+has read and processed them yet, on other OSes it counts only packets that were
+matched by the filter expression regardless of whether
+.I tcpdump
+has read and processed them yet, and on other OSes it counts only
+packets that were matched by the filter expression and were processed by
+.IR tcpdump );
+.IP
+packets ``dropped by kernel'' (this is the number of packets that were
+dropped, due to a lack of buffer space, by the packet capture mechanism
+in the OS on which

 .I tcpdump
 .I tcpdump

-you must have read access to
+is running, if the OS reports that information to applications; if not,
+it will be reported as 0).
+.LP
+On platforms that support the SIGINFO signal, such as most BSDs
+(including Mac OS X) and Digital/Tru64 UNIX, it will report those counts
+when it receives a SIGINFO signal (generated, for example, by typing
+your ``status'' character, typically control-T, although on some
+platforms, such as Mac OS X, the ``status'' character is not set by
+default, so you must set it with
+.BR stty (1)
+in order to use it) and will continue capturing packets.
+.LP
+Reading packets from a network interface may require that you have
+special privileges:
+.TP
+.B Under SunOS 3.x or 4.x with NIT or BPF:
+You must have read access to

 .I /dev/nit
 or
 .IR /dev/bpf* .
 .I /dev/nit
 or
 .IR /dev/bpf* .

-.B Under Solaris with dlpi:
-You must have read access to the network pseudo device, e.g.
+.TP
+.B Under Solaris with DLPI:
+You must have read/write access to the network pseudo device, e.g.

 .IR /dev/le .
 .IR /dev/le .

-.B Under HP-UX with dlpi:
-You must be root or it must be installed setuid to root.
+On at least some versions of Solaris, however, this is not sufficient to
+allow
+.I tcpdump
+to capture in promiscuous mode; on those versions of Solaris, you must
+be root, or
+.I tcpdump
+must be installed setuid to root, in order to capture in promiscuous
+mode.  Note that, on many (perhaps all) interfaces, if you don't capture
+in promiscuous mode, you will not see any outgoing packets, so a capture
+not done in promiscuous mode may not be very useful.
+.TP
+.B Under HP-UX with DLPI:
+You must be root or
+.I tcpdump
+must be installed setuid to root.
+.TP

 .B Under IRIX with snoop:
 .B Under IRIX with snoop:

-You must be root or it must be installed setuid to root.
+You must be root or
+.I tcpdump
+must be installed setuid to root.
+.TP

 .B Under Linux:
 .B Under Linux:

-You must be root or it must be installed setuid to root.
-.B Under Ultrix and Digital UNIX:
-Once the super-user has enabled promiscuous-mode operation using
+You must be root or
+.I tcpdump
+must be installed setuid to root (unless your distribution has a kernel
+that supports capability bits such as CAP_NET_RAW and code to allow
+those capability bits to be given to particular accounts and to cause
+those bits to be set on a user's initial processes when they log in, in
+which case you  must have CAP_NET_RAW in order to capture and
+CAP_NET_ADMIN to enumerate network devices with, for example, the
+.B \-D
+flag).
+.TP
+.B Under ULTRIX and Digital UNIX/Tru64 UNIX:
+Any user may capture network traffic with
+.IR tcpdump .
+However, no user (not even the super-user) can capture in promiscuous
+mode on an interface unless the super-user has enabled promiscuous-mode
+operation on that interface using

 .IR pfconfig (8),
 .IR pfconfig (8),

-any user may run
-.BR tcpdump .
-.B Under BSD:
+and no user (not even the super-user) can capture unicast traffic
+received by or sent by the machine on an interface unless the super-user
+has enabled copy-all-mode operation on that interface using
+.IR pfconfig ,
+so
+.I useful
+packet capture on an interface probably requires that either
+promiscuous-mode or copy-all-mode operation, or both modes of
+operation, be enabled on that interface.
+.TP
+.B Under BSD (this includes Mac OS X):

 You must have read access to
 .IR /dev/bpf* .
 You must have read access to
 .IR /dev/bpf* .

+On BSDs with a devfs (this includes Mac OS X), this might involve more
+than just having somebody with super-user access setting the ownership
+or permissions on the BPF devices - it might involve configuring devfs
+to set the ownership or permissions every time the system is booted,
+if the system even supports that; if it doesn't support that, you might
+have to find some other way to make that happen at boot time.
+.LP
+Reading a saved packet file doesn't require special privileges.

 .SH OPTIONS
 .TP
 .SH OPTIONS
 .TP

-.B \-a
-Attempt to convert network and broadcast addresses to names.
+.B \-A
+Print each packet (minus its link level header) in ASCII.  Handy for
+capturing web pages.

 .TP
 .B \-c
 Exit after receiving \fIcount\fP packets.
 .TP
 .TP
 .B \-c
 Exit after receiving \fIcount\fP packets.
 .TP

+.B \-C
+Before writing a raw packet to a savefile, check whether the file is
+currently larger than \fIfile_size\fP and, if so, close the current
+savefile and open a new one.  Savefiles after the first savefile will
+have the name specified with the
+.B \-w
+flag, with a number after it, starting at 1 and continuing upward.
+The units of \fIfile_size\fP are millions of bytes (1,000,000 bytes,
+not 1,048,576 bytes).
+.TP

 .B \-d
 Dump the compiled packet-matching code in a human readable form to
 standard output and stop.
 .B \-d
 Dump the compiled packet-matching code in a human readable form to
 standard output and stop.


@@ -119,14 +273,83 @@ program fragment.
 .B \-ddd
 Dump packet-matching code as decimal numbers (preceded with a count).
 .TP
 .B \-ddd
 Dump packet-matching code as decimal numbers (preceded with a count).
 .TP

+.B \-D
+Print the list of the network interfaces available on the system and on
+which
+.I tcpdump
+can capture packets.  For each network interface, a number and an
+interface name, possibly followed by a text description of the
+interface, is printed.  The interface name or the number can be supplied
+to the
+.B \-i
+flag to specify an interface on which to capture.
+.IP
+This can be useful on systems that don't have a command to list them
+(e.g., Windows systems, or UNIX systems lacking
+.BR "ifconfig \-a" );
+the number can be useful on Windows 2000 and later systems, where the
+interface name is a somewhat complex string.
+.IP
+The
+.B \-D
+flag will not be supported if
+.I tcpdump
+was built with an older version of
+.I libpcap
+that lacks the
+.B pcap_findalldevs()
+function.
+.TP

 .B \-e
 Print the link-level header on each dump line.
 .TP
 .B \-e
 Print the link-level header on each dump line.
 .TP

+.B \-E
+Use \fIspi@ipaddr algo:secret\fP for decrypting IPsec ESP packets that
+are addressed to \fIaddr\fP and contain Security Parameter Index value
+\fIspi\fP. This combination may be repeated with comma or newline seperation.
+.IP
+Note that setting the secret for IPv4 ESP packets is supported at this time.
+.IP
+Algorithms may be
+\fBdes-cbc\fP,
+\fB3des-cbc\fP,
+\fBblowfish-cbc\fP,
+\fBrc3-cbc\fP,
+\fBcast128-cbc\fP, or
+\fBnone\fP.
+The default is \fBdes-cbc\fP.
+The ability to decrypt packets is only present if \fItcpdump\fP was compiled
+with cryptography enabled.
+.IP
+\fIsecret\fP is the ASCII text for ESP secret key. 
+If preceeded by 0x, then a hex value will be read.
+.IP
+The option assumes RFC2406 ESP, not RFC1827 ESP.
+The option is only for debugging purposes, and
+the use of this option with a true `secret' key is discouraged.
+By presenting IPsec secret key onto command line
+you make it visible to others, via
+.IR ps (1)
+and other occasions.
+.IP
+In addition to the above syntax, the syntax \fIfile name\fP may be used
+to have tcpdump read the provided file in. The file is opened upon 
+receiving the first ESP packet, so any special permissions that tcpdump
+may have been given should already have been given up.
+.TP

 .B \-f
 .B \-f

-Print `foreign' internet addresses numerically rather than symbolically
+Print `foreign' IPv4 addresses numerically rather than symbolically

 (this option is intended to get around serious brain damage in
 (this option is intended to get around serious brain damage in

-Sun's yp server \(em usually it hangs forever translating non-local
+Sun's NIS server \(em usually it hangs forever translating non-local

 internet numbers).
 internet numbers).

+.IP
+The test for `foreign' IPv4 addresses is done using the IPv4 address and
+netmask of the interface on which capture is being done.  If that
+address or netmask are not available, available, either because the
+interface on which capture is being done has no address or netmask or
+because the capture is being done on the Linux "any" interface, which
+can capture on more than one interface, this option will not work
+correctly.

 .TP
 .B \-F
 Use \fIfile\fP as input for the filter expression.
 .TP
 .B \-F
 Use \fIfile\fP as input for the filter expression.


@@ -137,113 +360,237 @@ Listen on \fIinterface\fP.
 If unspecified, \fItcpdump\fP searches the system interface list for the
 lowest numbered, configured up interface (excluding loopback).
 Ties are broken by choosing the earliest match.
 If unspecified, \fItcpdump\fP searches the system interface list for the
 lowest numbered, configured up interface (excluding loopback).
 Ties are broken by choosing the earliest match.

+.IP
+On Linux systems with 2.2 or later kernels, an
+.I interface
+argument of ``any'' can be used to capture packets from all interfaces.
+Note that captures on the ``any'' device will not be done in promiscuous
+mode.
+.IP
+If the
+.B \-D
+flag is supported, an interface number as printed by that flag can be
+used as the
+.I interface
+argument.

 .TP
 .B \-l
 .TP
 .B \-l

-Make stdout line buffered.  Useful if you want to see the data
-while capturing it.  E.g.,
+Make stdout line buffered.
+Useful if you want to see the data
+while capturing it.
+E.g.,

 .br
 ``tcpdump\ \ \-l\ \ |\ \ tee dat'' or
 ``tcpdump\ \ \-l \ \ > dat\ \ &\ \ tail\ \ \-f\ \ dat''.
 .TP
 .br
 ``tcpdump\ \ \-l\ \ |\ \ tee dat'' or
 ``tcpdump\ \ \-l \ \ > dat\ \ &\ \ tail\ \ \-f\ \ dat''.
 .TP

+.B \-L
+List the known data link types for the interface and exit.
+.TP
+.B \-m
+Load SMI MIB module definitions from file \fImodule\fR.
+This option
+can be used several times to load several MIB modules into \fItcpdump\fP.
+.TP
+.B \-M
+Use \fIsecret\fP as a shared secret for validating the digests found in
+TCP segments with the TCP-MD5 option (RFC 2385), if present.
+.TP

 .B \-n
 Don't convert addresses (i.e., host addresses, port numbers, etc.) to names.
 .TP
 .B \-N
 .B \-n
 Don't convert addresses (i.e., host addresses, port numbers, etc.) to names.
 .TP
 .B \-N

-Don't print domain name qualification of host names.  E.g.,
+Don't print domain name qualification of host names.
+E.g.,

 if you give this flag then \fItcpdump\fP will print ``nic''
 instead of ``nic.ddn.mil''.
 .TP
 if you give this flag then \fItcpdump\fP will print ``nic''
 instead of ``nic.ddn.mil''.
 .TP

-.B \-m
-Load SMI MIB module definitions from file \fImodule\fR. This option 
-can be used several times to load several MIB modules into tcpdump.
-.TP

 .B \-O
 .B \-O

-Do not run the packet-matching code optimizer.  This is useful only
+Do not run the packet-matching code optimizer.
+This is useful only

 if you suspect a bug in the optimizer.
 .TP
 .B \-p
 \fIDon't\fP put the interface
 if you suspect a bug in the optimizer.
 .TP
 .B \-p
 \fIDon't\fP put the interface

-into promiscuous mode.  Note that the interface might be in promiscuous
+into promiscuous mode.
+Note that the interface might be in promiscuous

 mode for some other reason; hence, `-p' cannot be used as an abbreviation for
 `ether host {local-hw-addr} or ether broadcast'.
 .TP
 .B \-q
 mode for some other reason; hence, `-p' cannot be used as an abbreviation for
 `ether host {local-hw-addr} or ether broadcast'.
 .TP
 .B \-q

-Quick (quiet?) output.  Print less protocol information so output
+Quick (quiet?) output.
+Print less protocol information so output

 lines are shorter.
 .TP
 lines are shorter.
 .TP

+.B \-R
+Assume ESP/AH packets to be based on old specification (RFC1825 to RFC1829).
+If specified, \fItcpdump\fP will not print replay prevention field.
+Since there is no protocol version field in ESP/AH specification,
+\fItcpdump\fP cannot deduce the version of ESP/AH protocol.
+.TP

 .B \-r
 .B \-r

-Read packets from \fIfile\fR (which was created with the -w option).
+Read packets from \fIfile\fR (which was created with the
+.B \-w
+option).

 Standard input is used if \fIfile\fR is ``-''.
 .TP
 Standard input is used if \fIfile\fR is ``-''.
 .TP

+.B \-S
+Print absolute, rather than relative, TCP sequence numbers.
+.TP

 .B \-s
 Snarf \fIsnaplen\fP bytes of data from each packet rather than the
 default of 68 (with SunOS's NIT, the minimum is actually 96).
 68 bytes is adequate for IP, ICMP, TCP
 and UDP but may truncate protocol information from name server and NFS
 .B \-s
 Snarf \fIsnaplen\fP bytes of data from each packet rather than the
 default of 68 (with SunOS's NIT, the minimum is actually 96).
 68 bytes is adequate for IP, ICMP, TCP
 and UDP but may truncate protocol information from name server and NFS

-packets (see below).  Packets truncated because of a limited snapshot
+packets (see below).
+Packets truncated because of a limited snapshot

 are indicated in the output with ``[|\fIproto\fP]'', where \fIproto\fP
 is the name of the protocol level at which the truncation has occurred.
 Note that taking larger snapshots both increases
 the amount of time it takes to process packets and, effectively,
 are indicated in the output with ``[|\fIproto\fP]'', where \fIproto\fP
 is the name of the protocol level at which the truncation has occurred.
 Note that taking larger snapshots both increases
 the amount of time it takes to process packets and, effectively,

-decreases the amount of packet buffering.  This may cause packets to be
-lost.  You should limit \fIsnaplen\fP to the smallest number that will
+decreases the amount of packet buffering.
+This may cause packets to be
+lost.
+You should limit \fIsnaplen\fP to the smallest number that will

 capture the protocol information you're interested in.
 capture the protocol information you're interested in.

+Setting
+\fIsnaplen\fP to 0 means use the required length to catch whole packets.

 .TP
 .B \-T
 Force packets selected by "\fIexpression\fP" to be interpreted the
 .TP
 .B \-T
 Force packets selected by "\fIexpression\fP" to be interpreted the

-specified \fItype\fR. Currently known types are
+specified \fItype\fR.
+Currently known types are
+\fBaodv\fR (Ad-hoc On-demand Distance Vector protocol),
+\fBcnfp\fR (Cisco NetFlow protocol),

 \fBrpc\fR (Remote Procedure Call),
 \fBrtp\fR (Real-Time Applications protocol),
 \fBrtcp\fR (Real-Time Applications control protocol),
 \fBsnmp\fR (Simple Network Management Protocol),
 \fBrpc\fR (Remote Procedure Call),
 \fBrtp\fR (Real-Time Applications protocol),
 \fBrtcp\fR (Real-Time Applications control protocol),
 \fBsnmp\fR (Simple Network Management Protocol),

+\fBtftp\fR (Trivial File Transfer Protocol),

 \fBvat\fR (Visual Audio Tool),
 and
 \fBwb\fR (distributed White Board).
 .TP
 \fBvat\fR (Visual Audio Tool),
 and
 \fBwb\fR (distributed White Board).
 .TP

-.B \-R
-Assume ESP/AH packets to be based on old specification (RFC1825 to RFC1829).
-If specified, \fItcpdump\fP will not print replay prevention field.
-Since there is no protocol version field in ESP/AH specification,
-\fItcpdump\fP cannot deduce the version of ESP/AH protocol.
-.TP
-.B \-S
-Print absolute, rather than relative, TCP sequence numbers.
-.TP

 .B \-t
 \fIDon't\fP print a timestamp on each dump line.
 .TP
 .B \-tt
 Print an unformatted timestamp on each dump line.
 .TP
 .B \-t
 \fIDon't\fP print a timestamp on each dump line.
 .TP
 .B \-tt
 Print an unformatted timestamp on each dump line.
 .TP

+.B \-ttt
+Print a delta (in micro-seconds) between current and previous line
+on each dump line.
+.TP
+.B \-tttt
+Print a timestamp in default format proceeded by date on each dump line.
+.TP
+.B \-u
+Print undecoded NFS handles.
+.TP
+.B \-U
+Make output saved via the
+.B \-w
+option ``packet-buffered''; i.e., as each packet is saved, it will be
+written to the output file, rather than being written only when the
+output buffer fills.
+.IP
+The
+.B \-U
+flag will not be supported if
+.I tcpdump
+was built with an older version of
+.I libpcap
+that lacks the
+.B pcap_dump_flush()
+function.
+.TP

 .B \-v
 .B \-v

-(Slightly more) verbose output.  For example, the time to live
-and type of service information in an IP packet is printed.
+When parsing and printing, produce (slightly more) verbose output.
+For example, the time to live,
+identification, total length and options in an IP packet are printed.
+Also enables additional packet integrity checks such as verifying the
+IP and ICMP header checksum.
+.IP
+When writing to a file with the
+.B \-w
+option, report, every 10 seconds, the number of packets captured.

 .TP
 .B \-vv
 .TP
 .B \-vv

-Even more verbose output.  For example, additional fields are
-printed from NFS reply packets.
+Even more verbose output.
+For example, additional fields are
+printed from NFS reply packets, and SMB packets are fully decoded.
+.TP
+.B \-vvv
+Even more verbose output.
+For example,
+telnet \fBSB\fP ... \fBSE\fP options
+are printed in full.
+With
+.B \-X
+Telnet options are printed in hex as well.

 .TP
 .B \-w
 Write the raw packets to \fIfile\fR rather than parsing and printing
 .TP
 .B \-w
 Write the raw packets to \fIfile\fR rather than parsing and printing

-them out.  They can later be printed with the \-r option.
+them out.
+They can later be printed with the \-r option.

 Standard output is used if \fIfile\fR is ``-''.
 .TP
 Standard output is used if \fIfile\fR is ``-''.
 .TP

+.B \-W
+Used in conjunction with the 
+.I \-C 
+option, this will limit the number
+of files created to the specified number, and begin overwriting files
+from the beginning, thus creating a 'rotating' buffer. 
+In addition, it will name
+the files with enough leading 0s to support the maximum number of
+files, allowing them to sort correctly.
+.TP

 .B \-x
 Print each packet (minus its link level header) in hex.
 The smaller of the entire packet or
 .I snaplen
 .B \-x
 Print each packet (minus its link level header) in hex.
 The smaller of the entire packet or
 .I snaplen

-bytes will be printed.
+bytes will be printed.  Note that this is the entire link-layer
+packet, so for link layers that pad (e.g. Ethernet), the padding bytes
+will also be printed when the higher layer packet is shorter than the
+required padding.
+.TP
+.B \-xx
+Print each packet,
+.I including
+its link level header, in hex.
+.TP
+.B \-X
+Print each packet (minus its link level header) in hex and ASCII.
+This is very handy for analysing new protocols.
+.TP
+.B \-XX
+Print each packet,
+.I including
+its link level header, in hex and ASCII.
+.TP
+.B \-y
+Set the data link type to use while capturing packets to \fIdatalinktype\fP.
+.TP
+.B \-Z
+Drops privileges (if root) and changes user ID to
+.I user
+and the group ID to the primary group of
+.IR user .
+.IP
+This behavior can also be enabled by default at compile time.

 .IP "\fI expression\fP"
 .RS
 .IP "\fI expression\fP"
 .RS

-selects which packets will be dumped.  If no \fIexpression\fP
-is given, all packets on the net will be dumped.  Otherwise,
+selects which packets will be dumped.
+If no \fIexpression\fP
+is given, all packets on the net will be dumped.
+Otherwise,

 only packets for which \fIexpression\fP is `true' will be dumped.
 .LP
 The \fIexpression\fP consists of one or more
 .I primitives.
 Primitives usually consist of an
 .I id
 only packets for which \fIexpression\fP is `true' will be dumped.
 .LP
 The \fIexpression\fP consists of one or more
 .I primitives.
 Primitives usually consist of an
 .I id

-(name or number) preceded by one or more qualifiers.  There are three
+(name or number) preceded by one or more qualifiers.
+There are three

 different kinds of qualifier:
 .IP \fItype\fP
 qualifiers say what kind of thing the id name or number refers to.
 different kinds of qualifier:
 .IP \fItype\fP
 qualifiers say what kind of thing the id name or number refers to.


@@ -252,13 +599,14 @@ Possible types are
 .B net
 and
 .BR port .
 .B net
 and
 .BR port .

-E.g., `host foo', `net 128.3', `port 20'.  If there is no type
+E.g., `host foo', `net 128.3', `port 20'.
+If there is no type

 qualifier,
 .B host
 is assumed.
 .IP \fIdir\fP
 qualifiers specify a particular transfer direction to and/or from
 qualifier,
 .B host
 is assumed.
 .IP \fIdir\fP
 qualifiers specify a particular transfer direction to and/or from

-.I id.
+.IR id .

 Possible directions are
 .BR src ,
 .BR dst ,
 Possible directions are
 .BR src ,
 .BR dst ,


@@ -266,37 +614,38 @@ Possible directions are
 and
 .B "src and"
 .BR dst .
 and
 .B "src and"
 .BR dst .

-E.g., `src foo', `dst net 128.3', `src or dst port ftp-data'.  If
+E.g., `src foo', `dst net 128.3', `src or dst port ftp-data'.
+If

 there is no dir qualifier,
 .B "src or dst"
 is assumed.
 there is no dir qualifier,
 .B "src or dst"
 is assumed.

-For `null' link layers (i.e. point to point protocols such as slip) the
+For some link layers, such as SLIP and the ``cooked'' Linux capture mode
+used for the ``any'' device and for some other device types, the

 .B inbound
 and
 .B outbound
 qualifiers can be used to specify a desired direction.
 .IP \fIproto\fP
 .B inbound
 and
 .B outbound
 qualifiers can be used to specify a desired direction.
 .IP \fIproto\fP

-qualifiers restrict the match to a particular protocol.  Possible
+qualifiers restrict the match to a particular protocol.
+Possible

 protos are:
 .BR ether ,
 .BR fddi ,
 protos are:
 .BR ether ,
 .BR fddi ,

+.BR tr ,
+.BR wlan ,

 .BR ip ,
 .BR ip6 ,
 .BR arp ,
 .BR rarp ,
 .BR decnet ,
 .BR ip ,
 .BR ip6 ,
 .BR arp ,
 .BR rarp ,
 .BR decnet ,

-.BR lat ,
-.BR sca ,
-.BR moprc ,
-.BR mopdl ,
-.BR icmp ,
-.BR icmp6 ,

 .B tcp
 and
 .BR udp .
 .B tcp
 and
 .BR udp .

-E.g., `ether src foo', `arp net 128.3', `tcp port 21'.  If there is
+E.g., `ether src foo', `arp net 128.3', `tcp port 21'.
+If there is

 no proto qualifier, all protocols consistent with the type are
 no proto qualifier, all protocols consistent with the type are

-assumed.  E.g., `src foo' means `(ip or arp or rarp) src foo'
+assumed.
+E.g., `src foo' means `(ip or arp or rarp) src foo'

 (except the latter is not legal syntax), `net bar' means `(ip or
 arp or rarp) net bar' and `port 53' means `(tcp or udp) port 53'.
 .LP
 (except the latter is not legal syntax), `net bar' means `(ip or
 arp or rarp) net bar' and `port 53' means `(tcp or udp) port 53'.
 .LP


@@ -305,8 +654,15 @@ identically as meaning ``the data link level used on the specified
 network interface.''  FDDI headers contain Ethernet-like source
 and destination addresses, and often contain Ethernet-like packet
 types, so you can filter on these FDDI fields just as with the
 network interface.''  FDDI headers contain Ethernet-like source
 and destination addresses, and often contain Ethernet-like packet
 types, so you can filter on these FDDI fields just as with the

-analogous Ethernet fields.  FDDI headers also contain other fields,
-but you cannot name them explicitly in a filter expression.]
+analogous Ethernet fields.
+FDDI headers also contain other fields,
+but you cannot name them explicitly in a filter expression.
+.LP
+Similarly, `tr' and `wlan' are aliases for `ether'; the previous
+paragraph's statements about FDDI headers also apply to Token Ring
+and 802.11 wireless LAN headers.  For 802.11 headers, the destination
+address is the DA field and the source address is the SA field; the
+BSSID, RA, and TA fields aren't tested.]

 .LP
 In addition to the above, there are some special `primitive' keywords
 that don't follow the pattern:
 .LP
 In addition to the above, there are some special `primitive' keywords
 that don't follow the pattern:


@@ -314,15 +670,18 @@ that don't follow the pattern:
 .BR broadcast ,
 .BR less ,
 .B greater
 .BR broadcast ,
 .BR less ,
 .B greater

-and arithmetic expressions.  All of these are described below.
+and arithmetic expressions.
+All of these are described below.

 .LP
 More complex filter expressions are built up by using the words
 .BR and ,
 .B or
 and
 .B not
 .LP
 More complex filter expressions are built up by using the words
 .BR and ,
 .B or
 and
 .B not

-to combine primitives.  E.g., `host foo and not port ftp and not port ftp-data'.
-To save typing, identical qualifier lists can be omitted.  E.g.,
+to combine primitives.
+E.g., `host foo and not port ftp and not port ftp-data'.
+To save typing, identical qualifier lists can be omitted.
+E.g.,

 `tcp dst port ftp or ftp-data or domain' is exactly the same as
 `tcp dst port ftp or tcp dst port ftp-data or tcp dst port domain'.
 .LP
 `tcp dst port ftp or ftp-data or domain' is exactly the same as
 `tcp dst port ftp or tcp dst port ftp-data or tcp dst port domain'.
 .LP


@@ -350,7 +709,8 @@ which is equivalent to:
 If \fIhost\fR is a name with multiple IP addresses, each address will
 be checked for a match.
 .IP "\fBether dst \fIehost\fP
 If \fIhost\fR is a name with multiple IP addresses, each address will
 be checked for a match.
 .IP "\fBether dst \fIehost\fP

-True if the ethernet destination address is \fIehost\fP.  \fIEhost\fP
+True if the ethernet destination address is \fIehost\fP.
+\fIEhost\fP

 may be either a name from /etc/ethers or a number (see
 .IR ethers (3N)
 for numeric format).
 may be either a name from /etc/ethers or a number (see
 .IR ethers (3N)
 for numeric format).


@@ -359,11 +719,15 @@ True if the ethernet source address is \fIehost\fP.
 .IP "\fBether host \fIehost\fP
 True if either the ethernet source or destination address is \fIehost\fP.
 .IP "\fBgateway\fP \fIhost\fP
 .IP "\fBether host \fIehost\fP
 True if either the ethernet source or destination address is \fIehost\fP.
 .IP "\fBgateway\fP \fIhost\fP

-True if the packet used \fIhost\fP as a gateway.  I.e., the ethernet
+True if the packet used \fIhost\fP as a gateway.
+I.e., the ethernet

 source or destination address was \fIhost\fP but neither the IP source
 source or destination address was \fIhost\fP but neither the IP source

-nor the IP destination was \fIhost\fP.  \fIHost\fP must be a name and
-must be found in both /etc/hosts and /etc/ethers.  (An equivalent
-expression is
+nor the IP destination was \fIhost\fP.
+\fIHost\fP must be a name and
+must be found both by the machine's host-name-to-IP-address resolution
+mechanisms (host name file, DNS, NIS, etc.) and by the machine's
+host-name-to-Ethernet-address resolution mechanism (/etc/ethers, etc.).
+(An equivalent expression is

 .in +.5i
 .nf
 \fBether host \fIehost \fBand not host \fIhost\fR
 .in +.5i
 .nf
 \fBether host \fIehost \fBand not host \fIhost\fR


@@ -373,7 +737,8 @@ which can be used with either names or numbers for \fIhost / ehost\fP.)
 This syntax does not work in IPv6-enabled configuration at this moment.
 .IP "\fBdst net \fInet\fR"
 True if the IPv4/v6 destination address of the packet has a network
 This syntax does not work in IPv6-enabled configuration at this moment.
 .IP "\fBdst net \fInet\fR"
 True if the IPv4/v6 destination address of the packet has a network

-number of \fInet\fP. \fINet\fP may be either a name from /etc/networks
+number of \fInet\fP.
+\fINet\fP may be either a name from /etc/networks

 or a network number (see \fInetworks(4)\fP for details).
 .IP "\fBsrc net \fInet\fR"
 True if the IPv4/v6 source address of the packet has a network
 or a network number (see \fInetworks(4)\fP for details).
 .IP "\fBsrc net \fInet\fR"
 True if the IPv4/v6 source address of the packet has a network


@@ -381,12 +746,13 @@ number of \fInet\fP.
 .IP "\fBnet \fInet\fR"
 True if either the IPv4/v6 source or destination address of the packet has a network
 number of \fInet\fP.
 .IP "\fBnet \fInet\fR"
 True if either the IPv4/v6 source or destination address of the packet has a network
 number of \fInet\fP.

-.IP "\fBnet \fInet\fR \fBmask \fImask\fR"
-True if the IP address matches \fInet\fR with the specific netmask.
+.IP "\fBnet \fInet\fR \fBmask \fInetmask\fR"
+True if the IP address matches \fInet\fR with the specific \fInetmask\fR.

 May be qualified with \fBsrc\fR or \fBdst\fR.
 Note that this syntax is not valid for IPv6 \fInet\fR.
 .IP "\fBnet \fInet\fR/\fIlen\fR"
 May be qualified with \fBsrc\fR or \fBdst\fR.
 Note that this syntax is not valid for IPv6 \fInet\fR.
 .IP "\fBnet \fInet\fR/\fIlen\fR"

-True if the IPv4/v6 address matches \fInet\fR a netmask \fIlen\fR bits wide.
+True if the IPv4/v6 address matches \fInet\fR with a netmask \fIlen\fR
+bits wide.

 May be qualified with \fBsrc\fR or \fBdst\fR.
 .IP "\fBdst port \fIport\fR"
 True if the packet is ip/tcp, ip/udp, ip6/tcp or ip6/udp and has a
 May be qualified with \fBsrc\fR or \fBdst\fR.
 .IP "\fBdst port \fIport\fR"
 True if the packet is ip/tcp, ip/udp, ip6/tcp or ip6/udp and has a


@@ -396,7 +762,8 @@ The \fIport\fP can be a number or a name used in /etc/services (see
 and
 .IR udp (4P)).
 If a name is used, both the port
 and
 .IR udp (4P)).
 If a name is used, both the port

-number and protocol are checked.  If a number or ambiguous name is used,
+number and protocol are checked.
+If a number or ambiguous name is used,

 only the port number is checked (e.g., \fBdst port 513\fR will print both
 tcp/login traffic and udp/who traffic, and \fBport domain\fR will print
 both tcp/domain and udp/domain traffic).
 only the port number is checked (e.g., \fBdst port 513\fR will print both
 tcp/login traffic and udp/who traffic, and \fBport domain\fR will print
 both tcp/domain and udp/domain traffic).


@@ -429,17 +796,18 @@ This is equivalent to:
 .fi
 .in -.5i
 .IP "\fBip proto \fIprotocol\fR"
 .fi
 .in -.5i
 .IP "\fBip proto \fIprotocol\fR"

-True if the packet is an ip packet (see
+True if the packet is an IP packet (see

 .IR ip (4P))
 of protocol type \fIprotocol\fP.
 \fIProtocol\fP can be a number or one of the names
 .IR ip (4P))
 of protocol type \fIprotocol\fP.
 \fIProtocol\fP can be a number or one of the names

-\fIicmp\fP, \fIigrp\fP, \fIudp\fP, \fInd\fP, or \fItcp\fP.
+\fIicmp\fP, \fIicmp6\fP, \fIigmp\fP, \fIigrp\fP, \fIpim\fP, \fIah\fP,
+\fIesp\fP, \fIvrrp\fP, \fIudp\fP, or \fItcp\fP.

 Note that the identifiers \fItcp\fP, \fIudp\fP, and \fIicmp\fP are also
 keywords and must be escaped via backslash (\\), which is \\\\ in the C-shell.
 Note that the identifiers \fItcp\fP, \fIudp\fP, and \fIicmp\fP are also
 keywords and must be escaped via backslash (\\), which is \\\\ in the C-shell.

-Note that this primitive does not chase protocol header chain.
+Note that this primitive does not chase the protocol header chain.

 .IP "\fBip6 proto \fIprotocol\fR"
 True if the packet is an IPv6 packet of protocol type \fIprotocol\fP.
 .IP "\fBip6 proto \fIprotocol\fR"
 True if the packet is an IPv6 packet of protocol type \fIprotocol\fP.

-Note that this primitive does not chase protocol header chain.
+Note that this primitive does not chase the protocol header chain.

 .IP "\fBip6 protochain \fIprotocol\fR"
 True if the packet is IPv6 packet,
 and contains protocol header with type \fIprotocol\fR
 .IP "\fBip6 protochain \fIprotocol\fR"
 True if the packet is IPv6 packet,
 and contains protocol header with type \fIprotocol\fR


@@ -460,14 +828,23 @@ so this can be somewhat slow.
 .IP "\fBip protochain \fIprotocol\fR"
 Equivalent to \fBip6 protochain \fIprotocol\fR, but this is for IPv4.
 .IP "\fBether broadcast\fR"
 .IP "\fBip protochain \fIprotocol\fR"
 Equivalent to \fBip6 protochain \fIprotocol\fR, but this is for IPv4.
 .IP "\fBether broadcast\fR"

-True if the packet is an ethernet broadcast packet.  The \fIether\fP
+True if the packet is an ethernet broadcast packet.
+The \fIether\fP

 keyword is optional.
 .IP "\fBip broadcast\fR"
 keyword is optional.
 .IP "\fBip broadcast\fR"

-True if the packet is an IP broadcast packet.  It checks for both
-the all-zeroes and all-ones broadcast conventions, and looks up
-the local subnet mask.
+True if the packet is an IPv4 broadcast packet.
+It checks for both the all-zeroes and all-ones broadcast conventions,
+and looks up the subnet mask on the interface on which the capture is
+being done.
+.IP
+If the subnet mask of the interface on which the capture is being done
+is not available, either because the interface on which capture is being
+done has no netmask or because the capture is being done on the Linux
+"any" interface, which can capture on more than one interface, this
+check will not work correctly.

 .IP "\fBether multicast\fR"
 .IP "\fBether multicast\fR"

-True if the packet is an ethernet multicast packet.  The \fIether\fP
+True if the packet is an ethernet multicast packet.
+The \fIether\fP

 keyword is optional.
 This is shorthand for `\fBether[0] & 1 != 0\fP'.
 .IP "\fBip multicast\fR"
 keyword is optional.
 This is shorthand for `\fBether[0] & 1 != 0\fP'.
 .IP "\fBip multicast\fR"


@@ -476,21 +853,67 @@ True if the packet is an IP multicast packet.
 True if the packet is an IPv6 multicast packet.
 .IP  "\fBether proto \fIprotocol\fR"
 True if the packet is of ether type \fIprotocol\fR.
 True if the packet is an IPv6 multicast packet.
 .IP  "\fBether proto \fIprotocol\fR"
 True if the packet is of ether type \fIprotocol\fR.

-\fIProtocol\fP can be a number or a name like
-\fIip\fP, \fIip6\fP, \fIarp\fP, or \fIrarp\fP.
+\fIProtocol\fP can be a number or one of the names
+\fIip\fP, \fIip6\fP, \fIarp\fP, \fIrarp\fP, \fIatalk\fP, \fIaarp\fP,
+\fIdecnet\fP, \fIsca\fP, \fIlat\fP, \fImopdl\fP, \fImoprc\fP,
+\fIiso\fP, \fIstp\fP, \fIipx\fP, or \fInetbeui\fP.

 Note these identifiers are also keywords
 and must be escaped via backslash (\\).
 Note these identifiers are also keywords
 and must be escaped via backslash (\\).

-[In the case of FDDI (e.g., `\fBfddi protocol arp\fR'), the
-protocol identification comes from the 802.2 Logical Link Control
-(LLC) header, which is usually layered on top of the FDDI header.
-\fITcpdump\fP assumes, when filtering on the protocol identifier,
-that all FDDI packets include an LLC header, and that the LLC header
-is in so-called SNAP format.]
+.IP
+[In the case of FDDI (e.g., `\fBfddi protocol arp\fR'), Token Ring
+(e.g., `\fBtr protocol arp\fR'), and IEEE 802.11 wireless LANS (e.g.,
+`\fBwlan protocol arp\fR'), for most of those protocols, the
+protocol identification comes from the 802.2 Logical Link Control (LLC)
+header, which is usually layered on top of the FDDI, Token Ring, or
+802.11 header.
+.IP
+When filtering for most protocol identifiers on FDDI, Token Ring, or
+802.11, \fItcpdump\fR checks only the protocol ID field of an LLC header
+in so-called SNAP format with an Organizational Unit Identifier (OUI) of
+0x000000, for encapsulated Ethernet; it doesn't check whether the packet
+is in SNAP format with an OUI of 0x000000.
+The exceptions are:
+.RS
+.TP
+\fBiso\fP
+\fItcpdump\fR checks the DSAP (Destination Service Access Point) and
+SSAP (Source Service Access Point) fields of the LLC header;
+.TP
+\fBstp\fP and \fInetbeui\fP
+\fItcpdump\fR checks the DSAP of the LLC header;
+.TP
+\fIatalk\fP
+\fItcpdump\fR checks for a SNAP-format packet with an OUI of 0x080007
+and the AppleTalk etype.
+.RE
+.IP
+In the case of Ethernet, \fItcpdump\fR checks the Ethernet type field
+for most of those protocols.  The exceptions are:
+.RS
+.TP
+\fBiso\fP, \fBstp\fP, and \fBnetbeui\fP
+\fItcpdump\fR checks for an 802.3 frame and then checks the LLC header as
+it does for FDDI, Token Ring, and 802.11;
+.TP
+\fBatalk\fP
+\fItcpdump\fR checks both for the AppleTalk etype in an Ethernet frame and
+for a SNAP-format packet as it does for FDDI, Token Ring, and 802.11;
+.TP
+\fBaarp\fP
+\fItcpdump\fR checks for the AppleTalk ARP etype in either an Ethernet
+frame or an 802.2 SNAP frame with an OUI of 0x000000;
+.TP
+\fBipx\fP
+\fItcpdump\fR checks for the IPX etype in an Ethernet frame, the IPX
+DSAP in the LLC header, the 802.3-with-no-LLC-header encapsulation of
+IPX, and the IPX etype in a SNAP frame.
+.RE

 .IP "\fBdecnet src \fIhost\fR"
 True if the DECNET source address is
 .IR host ,
 which may be an address of the form ``10.123'', or a DECNET host
 .IP "\fBdecnet src \fIhost\fR"
 True if the DECNET source address is
 .IR host ,
 which may be an address of the form ``10.123'', or a DECNET host

-name.  [DECNET host name support is only available on Ultrix systems
+name.
+[DECNET host name support is only available on ULTRIX systems

 that are configured to run DECNET.]
 .IP "\fBdecnet dst \fIhost\fR"
 True if the DECNET destination address is
 that are configured to run DECNET.]
 .IP "\fBdecnet dst \fIhost\fR"
 True if the DECNET destination address is


@@ -498,7 +921,59 @@ True if the DECNET destination address is
 .IP "\fBdecnet host \fIhost\fR"
 True if either the DECNET source or destination address is
 .IR host .
 .IP "\fBdecnet host \fIhost\fR"
 True if either the DECNET source or destination address is
 .IR host .

-.IP "\fBip\fR, \fBip6\fR, \fBarp\fR, \fBrarp\fR, \fBdecnet\fR"
+.IP "\fBifname \fIinterface\fR"
+True if the packet was logged as coming from the specified interface (applies
+only to packets logged by OpenBSD's
+.BR pf (4)).
+.IP "\fBon \fIinterface\fR"
+Synonymous with the
+.B ifname
+modifier.
+.IP "\fBrnr \fInum\fR"
+True if the packet was logged as matching the specified PF rule number
+(applies only to packets logged by OpenBSD's
+.BR pf (4)).
+.IP "\fBrulenum \fInum\fR"
+Synonomous with the
+.B rnr
+modifier.
+.IP "\fBreason \fIcode\fR"
+True if the packet was logged with the specified PF reason code.  The known
+codes are:
+.BR match ,
+.BR bad-offset ,
+.BR fragment ,
+.BR short ,
+.BR normalize ,
+and
+.B memory
+(applies only to packets logged by OpenBSD's
+.BR pf (4)).
+.IP "\fBrset \fIname\fR"
+True if the packet was logged as matching the specified PF ruleset
+name of an anchored ruleset (applies only to packets logged by
+.BR pf (4)).
+.IP "\fBruleset \fIname\fR"
+Synonomous with the
+.B rset
+modifier.
+.IP "\fBsrnr \fInum\fR"
+True if the packet was logged as matching the specified PF rule number
+of an anchored ruleset (applies only to packets logged by
+.BR pf (4)).
+.IP "\fBsubrulenum \fInum\fR"
+Synonomous with the
+.B srnr
+modifier.
+.IP "\fBaction \fIact\fR"
+True if PF took the specified action when the packet was logged.  Known actions
+are:
+.B pass
+and
+.B block
+(applies only to packets logged by OpenBSD's
+.BR pf (4)).
+.IP "\fBip\fR, \fBip6\fR, \fBarp\fR, \fBrarp\fR, \fBatalk\fR, \fBaarp\fR, \fBdecnet\fR, \fBiso\fR, \fBstp\fR, \fBipx\fR, \fInetbeui\fP"

 Abbreviations for:
 .in +.5i
 .nf
 Abbreviations for:
 .in +.5i
 .nf


@@ -516,6 +991,13 @@ Abbreviations for:
 where \fIp\fR is one of the above protocols.
 Note that
 \fItcpdump\fP does not currently know how to parse these protocols.
 where \fIp\fR is one of the above protocols.
 Note that
 \fItcpdump\fP does not currently know how to parse these protocols.

+.IP "\fBvlan \fI[vlan_id]\fR"
+True if the packet is an IEEE 802.1Q VLAN packet.
+If \fI[vlan_id]\fR is specified, only true is the packet has the specified
+\fIvlan_id\fR.
+Note that the first \fBvlan\fR keyword encountered in \fIexpression\fR
+changes the decoding offsets for the remainder of \fIexpression\fR
+on the assumption that the packet is a VLAN packet.

 .IP  "\fBtcp\fR, \fBudp\fR, \fBicmp\fR"
 Abbreviations for:
 .in +.5i
 .IP  "\fBtcp\fR, \fBudp\fR, \fBicmp\fR"
 Abbreviations for:
 .in +.5i


@@ -524,11 +1006,78 @@ Abbreviations for:
 .fi
 .in -.5i
 where \fIp\fR is one of the above protocols.
 .fi
 .in -.5i
 where \fIp\fR is one of the above protocols.

+.IP "\fBiso proto \fIprotocol\fR"
+True if the packet is an OSI packet of protocol type \fIprotocol\fP.
+\fIProtocol\fP can be a number or one of the names
+\fIclnp\fP, \fIesis\fP, or \fIisis\fP.
+.IP "\fBclnp\fR, \fBesis\fR, \fBisis\fR"
+Abbreviations for:
+.in +.5i
+.nf
+\fBiso proto \fIp\fR
+.fi
+.in -.5i
+where \fIp\fR is one of the above protocols.
+.IP "\fBl1\fR, \fBl2\fR, \fBiih\fR, \fBlsp\fR, \fBsnp\fR, \fBcsnp\fR, \fBpsnp\fR"
+Abbreviations for IS-IS PDU types.
+.IP "\fBvpi\fP \fIn\fR
+True if the packet is an ATM packet, for SunATM on Solaris, with a
+virtual path identifier of
+.IR n .
+.IP "\fBvci\fP \fIn\fR
+True if the packet is an ATM packet, for SunATM on Solaris, with a
+virtual channel identifier of
+.IR n .
+.IP \fBlane\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+an ATM LANE packet.
+Note that the first \fBlane\fR keyword encountered in \fIexpression\fR
+changes the tests done in the remainder of \fIexpression\fR
+on the assumption that the packet is either a LANE emulated Ethernet
+packet or a LANE LE Control packet.  If \fBlane\fR isn't specified, the
+tests are done under the assumption that the packet is an
+LLC-encapsulated packet.
+.IP \fBllc\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+an LLC-encapsulated packet.
+.IP \fBoamf4s\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+a segment OAM F4 flow cell (VPI=0 & VCI=3).
+.IP \fBoamf4e\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+an end-to-end OAM F4 flow cell (VPI=0 & VCI=4).
+.IP \fBoamf4\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+a segment or end-to-end OAM F4 flow cell (VPI=0 & (VCI=3 | VCI=4)).
+.IP \fBoam\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+a segment or end-to-end OAM F4 flow cell (VPI=0 & (VCI=3 | VCI=4)).
+.IP \fBmetac\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+on a meta signaling circuit (VPI=0 & VCI=1).
+.IP \fBbcc\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+on a broadcast signaling circuit (VPI=0 & VCI=2).
+.IP \fBsc\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+on a signaling circuit (VPI=0 & VCI=5).
+.IP \fBilmic\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+on an ILMI circuit (VPI=0 & VCI=16).
+.IP \fBconnectmsg\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+on a signaling circuit and is a Q.2931 Setup, Call Proceeding, Connect,
+Connect Ack, Release, or Release Done message.
+.IP \fBmetaconnect\fP
+True if the packet is an ATM packet, for SunATM on Solaris, and is
+on a meta signaling circuit and is a Q.2931 Setup, Call Proceeding, Connect,
+Release, or Release Done message.

 .IP  "\fIexpr relop expr\fR"
 .IP  "\fIexpr relop expr\fR"

-True if the relation holds, where \fIrelop\fR is one of >, <, >=, <=, =, !=,
-and \fIexpr\fR is an arithmetic expression composed of integer constants
-(expressed in standard C syntax), the normal binary operators
-[+, -, *, /, &, |], a length operator, and special packet data accessors.
+True if the relation holds, where \fIrelop\fR is one of >, <, >=, <=, =,
+!=, and \fIexpr\fR is an arithmetic expression composed of integer
+constants (expressed in standard C syntax), the normal binary operators
+[+, -, *, /, &, |, <<, >>], a length operator, and special packet data
+accessors.

 To access
 data inside the packet, use the following syntax:
 .in +.5i
 To access
 data inside the packet, use the following syntax:
 .in +.5i


@@ -536,9 +1085,11 @@ data inside the packet, use the following syntax:
 \fIproto\fB [ \fIexpr\fB : \fIsize\fB ]\fR
 .fi
 .in -.5i
 \fIproto\fB [ \fIexpr\fB : \fIsize\fB ]\fR
 .fi
 .in -.5i

-\fIProto\fR is one of \fBether, fddi,
+\fIProto\fR is one of \fBether, fddi, tr, wlan, ppp, slip, link,

 ip, arp, rarp, tcp, udp, icmp\fR or \fBip6\fR, and
 indicates the protocol layer for the index operation.
 ip, arp, rarp, tcp, udp, icmp\fR or \fBip6\fR, and
 indicates the protocol layer for the index operation.

+(\fBether, fddi, wlan, tr, ppp, slip\fR and \fBlink\fR all refer to the
+link layer.)

 Note that \fItcp, udp\fR and other upper-layer protocol types only
 apply to IPv4, not IPv6 (this will be fixed in the future).
 The byte offset, relative to the indicated protocol layer, is
 Note that \fItcp, udp\fR and other upper-layer protocol types only
 apply to IPv4, not IPv6 (this will be fixed in the future).
 The byte offset, relative to the indicated protocol layer, is


@@ -550,7 +1101,8 @@ length of the packet.
 
 For example, `\fBether[0] & 1 != 0\fP' catches all multicast traffic.
 The expression `\fBip[0] & 0xf != 5\fP'
 
 For example, `\fBether[0] & 1 != 0\fP' catches all multicast traffic.
 The expression `\fBip[0] & 0xf != 5\fP'

-catches all IP packets with options. The expression
+catches all IP packets with options.
+The expression

 `\fBip[6:2] & 0x1fff = 0\fP'
 catches only unfragmented datagrams and frag zero of fragmented datagrams.
 This check is implicitly applied to the \fBtcp\fP and \fBudp\fP
 `\fBip[6:2] & 0x1fff = 0\fP'
 catches only unfragmented datagrams and frag zero of fragmented datagrams.
 This check is implicitly applied to the \fBtcp\fP and \fBudp\fP


@@ -558,6 +1110,23 @@ index operations.
 For instance, \fBtcp[0]\fP always means the first
 byte of the TCP \fIheader\fP, and never means the first byte of an
 intervening fragment.
 For instance, \fBtcp[0]\fP always means the first
 byte of the TCP \fIheader\fP, and never means the first byte of an
 intervening fragment.

+
+Some offsets and field values may be expressed as names rather than
+as numeric values.
+The following protocol header field offsets are
+available: \fBicmptype\fP (ICMP type field), \fBicmpcode\fP (ICMP
+code field), and \fBtcpflags\fP (TCP flags field).
+
+The following ICMP type field values are available: \fBicmp-echoreply\fP,
+\fBicmp-unreach\fP, \fBicmp-sourcequench\fP, \fBicmp-redirect\fP,
+\fBicmp-echo\fP, \fBicmp-routeradvert\fP, \fBicmp-routersolicit\fP,
+\fBicmp-timxceed\fP, \fBicmp-paramprob\fP, \fBicmp-tstamp\fP,
+\fBicmp-tstampreply\fP, \fBicmp-ireq\fP, \fBicmp-ireqreply\fP,
+\fBicmp-maskreq\fP, \fBicmp-maskreply\fP.
+
+The following TCP flags field values are available: \fBtcp-fin\fP,
+\fBtcp-syn\fP, \fBtcp-rst\fP, \fBtcp-push\fP,
+\fBtcp-ack\fP, \fBtcp-urg\fP.

 .LP
 Primitives may be combined using:
 .IP
 .LP
 Primitives may be combined using:
 .IP


@@ -572,7 +1141,8 @@ Alternation (`\fB||\fP' or `\fBor\fP').
 .LP
 Negation has highest precedence.
 Alternation and concatenation have equal precedence and associate
 .LP
 Negation has highest precedence.
 Alternation and concatenation have equal precedence and associate

-left to right.  Note that explicit \fBand\fR tokens, not juxtaposition,
+left to right.
+Note that explicit \fBand\fR tokens, not juxtaposition,

 are now required for concatenation.
 .LP
 If an identifier is given without a keyword, the most recent keyword
 are now required for concatenation.
 .LP
 If an identifier is given without a keyword, the most recent keyword


@@ -596,8 +1166,8 @@ which should not be confused with
 .fi
 .in -.5i
 .LP
 .fi
 .in -.5i
 .LP

-Expression arguments can be passed to tcpdump as either a single argument
-or as multiple arguments, whichever is more convenient.
+Expression arguments can be passed to \fItcpdump\fP as either a single
+argument or as multiple arguments, whichever is more convenient.

 Generally, if the expression contains Shell metacharacters, it is
 easier to pass it as a single, quoted argument.
 Multiple arguments are concatenated with spaces before being parsed.
 Generally, if the expression contains Shell metacharacters, it is
 easier to pass it as a single, quoted argument.
 Multiple arguments are concatenated with spaces before being parsed.


@@ -657,7 +1227,7 @@ TCP conversation that involves a non-local host.
 .RS
 .nf
 .B
 .RS
 .nf
 .B

-tcpdump 'tcp[13] & 3 != 0 and not src and dst net \fIlocalnet\fP'
+tcpdump 'tcp[tcpflags] & (tcp-syn|tcp-fin) != 0 and not src and dst net \fIlocalnet\fP'

 .fi
 .RE
 .LP
 .fi
 .RE
 .LP


@@ -684,12 +1254,13 @@ ping packets):
 .RS
 .nf
 .B
 .RS
 .nf
 .B

-tcpdump 'icmp[0] != 8 and icmp[0] != 0"
+tcpdump 'icmp[icmptype] != icmp-echo and icmp[icmptype] != icmp-echoreply'

 .fi
 .RE
 .SH OUTPUT FORMAT
 .LP
 .fi
 .RE
 .SH OUTPUT FORMAT
 .LP

-The output of \fItcpdump\fP is protocol dependent.  The following
+The output of \fItcpdump\fP is protocol dependent.
+The following

 gives a brief description and examples of most of the formats.
 .de HD
 .sp 1.5
 gives a brief description and examples of most of the formats.
 .de HD
 .sp 1.5


@@ -704,14 +1275,32 @@ and packet length are printed.
 .LP
 On FDDI networks, the  '-e' option causes \fItcpdump\fP to print
 the `frame control' field,  the source and destination addresses,
 .LP
 On FDDI networks, the  '-e' option causes \fItcpdump\fP to print
 the `frame control' field,  the source and destination addresses,

-and the packet length.  (The `frame control' field governs the
-interpretation of the rest of the packet.  Normal packets (such
+and the packet length.
+(The `frame control' field governs the
+interpretation of the rest of the packet.
+Normal packets (such

 as those containing IP datagrams) are `async' packets, with a priority
 as those containing IP datagrams) are `async' packets, with a priority

-value between 0 and 7; for example, `\fBasync4\fR'.  Such packets
+value between 0 and 7; for example, `\fBasync4\fR'.
+Such packets

 are assumed to contain an 802.2 Logical Link Control (LLC) packet;
 the LLC header is printed if it is \fInot\fR an ISO datagram or a
 so-called SNAP packet.
 .LP
 are assumed to contain an 802.2 Logical Link Control (LLC) packet;
 the LLC header is printed if it is \fInot\fR an ISO datagram or a
 so-called SNAP packet.
 .LP

+On Token Ring networks, the '-e' option causes \fItcpdump\fP to print
+the `access control' and `frame control' fields, the source and
+destination addresses, and the packet length.
+As on FDDI networks,
+packets are assumed to contain an LLC packet.
+Regardless of whether
+the '-e' option is specified or not, the source routing information is
+printed for source-routed packets.
+.LP
+On 802.11 networks, the '-e' option causes \fItcpdump\fP to print
+the `frame control' fields, all of the addresses in the 802.11 header,
+and the packet length.
+As on FDDI networks,
+packets are assumed to contain an LLC packet.
+.LP

 \fI(N.B.: The following description assumes familiarity with
 the SLIP compression algorithm described in RFC-1144.)\fP
 .LP
 \fI(N.B.: The following description assumes familiarity with
 the SLIP compression algorithm described in RFC-1144.)\fP
 .LP


@@ -745,7 +1334,8 @@ data and 6 bytes of compressed header:
 .HD
 ARP/RARP Packets
 .LP
 .HD
 ARP/RARP Packets
 .LP

-Arp/rarp output shows the type of request and its arguments.  The
+Arp/rarp output shows the type of request and its arguments.
+The

 format is intended to be self explanatory.
 Here is a short sample taken from the start of an `rlogin' from
 host \fIrtsg\fP to host \fIcsam\fP:
 format is intended to be self explanatory.
 Here is a short sample taken from the start of an `rlogin' from
 host \fIrtsg\fP to host \fIcsam\fP:


@@ -753,16 +1343,17 @@ host \fIrtsg\fP to host \fIcsam\fP:
 .nf
 .sp .5
 \f(CWarp who-has csam tell rtsg
 .nf
 .sp .5
 \f(CWarp who-has csam tell rtsg

-arp reply csam is-at CSAM\fP
+arp reply csam is-at CSAM\fR

 .sp .5
 .fi
 .RE
 The first line says that rtsg sent an arp packet asking
 .sp .5
 .fi
 .RE
 The first line says that rtsg sent an arp packet asking

-for the ethernet address of internet host csam.  Csam
+for the ethernet address of internet host csam.
+Csam

 replies with its ethernet address (in this example, ethernet addresses
 are in caps and internet addresses in lower case).
 .LP
 replies with its ethernet address (in this example, ethernet addresses
 are in caps and internet addresses in lower case).
 .LP

-This would look less redundant if we had done \fBtcpdump \-n\fP:
+This would look less redundant if we had done \fItcpdump \-n\fP:

 .RS
 .nf
 .sp .5
 .RS
 .nf
 .sp .5


@@ -771,13 +1362,13 @@ arp reply 128.3.254.6 is-at 02:07:01:00:01:c4\fP
 .fi
 .RE
 .LP
 .fi
 .RE
 .LP

-If we had done \fBtcpdump \-e\fP, the fact that the first packet is
+If we had done \fItcpdump \-e\fP, the fact that the first packet is

 broadcast and the second is point-to-point would be visible:
 .RS
 .nf
 .sp .5
 \f(CWRTSG Broadcast 0806  64: arp who-has csam tell rtsg
 broadcast and the second is point-to-point would be visible:
 .RS
 .nf
 .sp .5
 \f(CWRTSG Broadcast 0806  64: arp who-has csam tell rtsg

-CSAM RTSG 0806  64: arp reply csam is-at CSAM\fP
+CSAM RTSG 0806  64: arp reply csam is-at CSAM\fR

 .sp .5
 .fi
 .RE
 .sp .5
 .fi
 .RE


@@ -788,8 +1379,9 @@ contained hex 0806 (type ETHER_ARP) and the total length was 64 bytes.
 TCP Packets
 .LP
 \fI(N.B.:The following description assumes familiarity with
 TCP Packets
 .LP
 \fI(N.B.:The following description assumes familiarity with

-the TCP protocol described in RFC-793.  If you are not familiar
-with the protocol, neither this description nor tcpdump will
+the TCP protocol described in RFC-793.
+If you are not familiar
+with the protocol, neither this description nor \fItcpdump\fP will

 be of much use to you.)\fP
 .LP
 The general format of a tcp protocol line is:
 be of much use to you.)\fP
 .LP
 The general format of a tcp protocol line is:


@@ -801,8 +1393,10 @@ The general format of a tcp protocol line is:
 .fi
 .RE
 \fISrc\fP and \fIdst\fP are the source and destination IP
 .fi
 .RE
 \fISrc\fP and \fIdst\fP are the source and destination IP

-addresses and ports.  \fIFlags\fP are some combination of S (SYN),
-F (FIN), P (PUSH) or R (RST) or a single `.' (no flags).
+addresses and ports.
+\fIFlags\fP are some combination of S (SYN),
+F (FIN), P (PUSH), R (RST), W (ECN CWR) or E (ECN-Echo), or a single
+`.' (no flags).

 \fIData-seqno\fP describes the portion of sequence space covered
 by the data in this packet (see example below).
 \fIAck\fP is sequence number of the next data expected the other
 \fIData-seqno\fP describes the portion of sequence space covered
 by the data in this packet (see example below).
 \fIAck\fP is sequence number of the next data expected the other


@@ -812,7 +1406,8 @@ the other direction on this connection.
 \fIUrg\fP indicates there is `urgent' data in the packet.
 \fIOptions\fP are tcp options enclosed in angle brackets (e.g., <mss 1024>).
 .LP
 \fIUrg\fP indicates there is `urgent' data in the packet.
 \fIOptions\fP are tcp options enclosed in angle brackets (e.g., <mss 1024>).
 .LP

-\fISrc, dst\fP and \fIflags\fP are always present.  The other fields
+\fISrc, dst\fP and \fIflags\fP are always present.
+The other fields

 depend on the contents of the packet's tcp protocol header and
 are output only if appropriate.
 .LP
 depend on the contents of the packet's tcp protocol header and
 are output only if appropriate.
 .LP


@@ -829,13 +1424,14 @@ csam.login > rtsg.1023: . ack 2 win 4096
 rtsg.1023 > csam.login: P 2:21(19) ack 1 win 4096
 csam.login > rtsg.1023: P 1:2(1) ack 21 win 4077
 csam.login > rtsg.1023: P 2:3(1) ack 21 win 4077 urg 1
 rtsg.1023 > csam.login: P 2:21(19) ack 1 win 4096
 csam.login > rtsg.1023: P 1:2(1) ack 21 win 4077
 csam.login > rtsg.1023: P 2:3(1) ack 21 win 4077 urg 1

-csam.login > rtsg.1023: P 3:4(1) ack 21 win 4077 urg 1\fP\s+2
+csam.login > rtsg.1023: P 3:4(1) ack 21 win 4077 urg 1\fR\s+2

 .sp .5
 .fi
 .RE
 The first line says that tcp port 1023 on rtsg sent a packet
 to port \fIlogin\fP
 .sp .5
 .fi
 .RE
 The first line says that tcp port 1023 on rtsg sent a packet
 to port \fIlogin\fP

-on csam.  The \fBS\fP indicates that the \fISYN\fP flag was set.
+on csam.
+The \fBS\fP indicates that the \fISYN\fP flag was set.

 The packet sequence number was 768512 and it contained no data.
 (The notation is `first:last(nbytes)' which means `sequence
 numbers \fIfirst\fP
 The packet sequence number was 768512 and it contained no data.
 (The notation is `first:last(nbytes)' which means `sequence
 numbers \fIfirst\fP


@@ -845,39 +1441,239 @@ bytes and there was a max-segment-size option requesting an mss of
 1024 bytes.
 .LP
 Csam replies with a similar packet except it includes a piggy-backed
 1024 bytes.
 .LP
 Csam replies with a similar packet except it includes a piggy-backed

-ack for rtsg's SYN.  Rtsg then acks csam's SYN.  The `.' means no
+ack for rtsg's SYN.
+Rtsg then acks csam's SYN.
+The `.' means no

 flags were set.
 The packet contained no data so there is no data sequence number.
 Note that the ack sequence
 flags were set.
 The packet contained no data so there is no data sequence number.
 Note that the ack sequence

-number is a small integer (1).  The first time \fBtcpdump\fP sees a
+number is a small integer (1).
+The first time \fItcpdump\fP sees a

 tcp `conversation', it prints the sequence number from the packet.
 On subsequent packets of the conversation, the difference between
 the current packet's sequence number and this initial sequence number
 tcp `conversation', it prints the sequence number from the packet.
 On subsequent packets of the conversation, the difference between
 the current packet's sequence number and this initial sequence number

-is printed.  This means that sequence numbers after the
+is printed.
+This means that sequence numbers after the

 first can be interpreted
 as relative byte positions in the conversation's data stream (with the
 first can be interpreted
 as relative byte positions in the conversation's data stream (with the

-first data byte each direction being `1').  `-S' will override this
+first data byte each direction being `1').
+`-S' will override this

 feature, causing the original sequence numbers to be output.
 .LP
 On the 6th line, rtsg sends csam 19 bytes of data (bytes 2 through 20
 in the rtsg \(-> csam side of the conversation).
 The PUSH flag is set in the packet.
 On the 7th line, csam says it's received data sent by rtsg up to
 feature, causing the original sequence numbers to be output.
 .LP
 On the 6th line, rtsg sends csam 19 bytes of data (bytes 2 through 20
 in the rtsg \(-> csam side of the conversation).
 The PUSH flag is set in the packet.
 On the 7th line, csam says it's received data sent by rtsg up to

-but not including byte 21.  Most of this data is apparently sitting in the
+but not including byte 21.
+Most of this data is apparently sitting in the

 socket buffer since csam's receive window has gotten 19 bytes smaller.
 Csam also sends one byte of data to rtsg in this packet.
 On the 8th and 9th lines,
 csam sends two bytes of urgent, pushed data to rtsg.
 .LP
 socket buffer since csam's receive window has gotten 19 bytes smaller.
 Csam also sends one byte of data to rtsg in this packet.
 On the 8th and 9th lines,
 csam sends two bytes of urgent, pushed data to rtsg.
 .LP

-If the snapshot was small enough that \fBtcpdump\fP didn't capture
+If the snapshot was small enough that \fItcpdump\fP didn't capture

 the full TCP header, it interprets as much of the header as it can
 and then reports ``[|\fItcp\fP]'' to indicate the remainder could not
 the full TCP header, it interprets as much of the header as it can
 and then reports ``[|\fItcp\fP]'' to indicate the remainder could not

-be interpreted.  If the header contains a bogus option (one with a length
-that's either too small or beyond the end of the header), tcpdump reports
-it as ``[\fIbad opt\fP]'' and does not interpret any further options (since
-it's impossible to tell where they start).  If the header length indicates
-options are present but the IP datagram length is not long enough for the
-options to actually be there, tcpdump reports it as ``[\fIbad hdr length\fP]''.
+be interpreted.
+If the header contains a bogus option (one with a length
+that's either too small or beyond the end of the header), \fItcpdump\fP
+reports it as ``[\fIbad opt\fP]'' and does not interpret any further
+options (since it's impossible to tell where they start).
+If the header
+length indicates options are present but the IP datagram length is not
+long enough for the options to actually be there, \fItcpdump\fP reports
+it as ``[\fIbad hdr length\fP]''.
+.HD
+.B Capturing TCP packets with particular flag combinations (SYN-ACK, URG-ACK, etc.)
+.PP
+There are 8 bits in the control bits section of the TCP header:
+.IP
+.I CWR | ECE | URG | ACK | PSH | RST | SYN | FIN
+.PP
+Let's assume that we want to watch packets used in establishing
+a TCP connection.
+Recall that TCP uses a 3-way handshake protocol
+when it initializes a new connection; the connection sequence with
+regard to the TCP control bits is
+.PP
+.RS
+1) Caller sends SYN
+.RE
+.RS
+2) Recipient responds with SYN, ACK
+.RE
+.RS
+3) Caller sends ACK
+.RE
+.PP
+Now we're interested in capturing packets that have only the
+SYN bit set (Step 1).
+Note that we don't want packets from step 2
+(SYN-ACK), just a plain initial SYN.
+What we need is a correct filter
+expression for \fItcpdump\fP.
+.PP
+Recall the structure of a TCP header without options:
+.PP
+.nf
+ 0                            15                              31
+-----------------------------------------------------------------
+|          source port          |       destination port        |
+-----------------------------------------------------------------
+|                        sequence number                        |
+-----------------------------------------------------------------
+|                     acknowledgment number                     |
+-----------------------------------------------------------------
+|  HL   | rsvd  |C|E|U|A|P|R|S|F|        window size            |
+-----------------------------------------------------------------
+|         TCP checksum          |       urgent pointer          |
+-----------------------------------------------------------------
+.fi
+.PP
+A TCP header usually holds 20 octets of data, unless options are
+present.
+The first line of the graph contains octets 0 - 3, the
+second line shows octets 4 - 7 etc.
+.PP
+Starting to count with 0, the relevant TCP control bits are contained
+in octet 13:
+.PP
+.nf
+ 0             7|             15|             23|             31
+----------------|---------------|---------------|----------------
+|  HL   | rsvd  |C|E|U|A|P|R|S|F|        window size            |
+----------------|---------------|---------------|----------------
+|               |  13th octet   |               |               |
+.fi
+.PP
+Let's have a closer look at octet no. 13:
+.PP
+.nf
+                |               |
+                |---------------|
+                |C|E|U|A|P|R|S|F|
+                |---------------|
+                |7   5   3     0|
+.fi
+.PP
+These are the TCP control bits we are interested
+in.
+We have numbered the bits in this octet from 0 to 7, right to
+left, so the PSH bit is bit number 3, while the URG bit is number 5.
+.PP
+Recall that we want to capture packets with only SYN set.
+Let's see what happens to octet 13 if a TCP datagram arrives
+with the SYN bit set in its header:
+.PP
+.nf
+                |C|E|U|A|P|R|S|F|
+                |---------------|
+                |0 0 0 0 0 0 1 0|
+                |---------------|
+                |7 6 5 4 3 2 1 0|
+.fi
+.PP
+Looking at the
+control bits section we see that only bit number 1 (SYN) is set.
+.PP
+Assuming that octet number 13 is an 8-bit unsigned integer in
+network byte order, the binary value of this octet is
+.IP
+00000010
+.PP
+and its decimal representation is
+.PP
+.nf
+   7     6     5     4     3     2     1     0
+0*2 + 0*2 + 0*2 + 0*2 + 0*2 + 0*2 + 1*2 + 0*2  =  2
+.fi
+.PP
+We're almost done, because now we know that if only SYN is set,
+the value of the 13th octet in the TCP header, when interpreted
+as a 8-bit unsigned integer in network byte order, must be exactly 2.
+.PP
+This relationship can be expressed as
+.RS
+.B
+tcp[13] == 2
+.RE
+.PP
+We can use this expression as the filter for \fItcpdump\fP in order
+to watch packets which have only SYN set:
+.RS
+.B
+tcpdump -i xl0 tcp[13] == 2
+.RE
+.PP
+The expression says "let the 13th octet of a TCP datagram have
+the decimal value 2", which is exactly what we want.
+.PP
+Now, let's assume that we need to capture SYN packets, but we
+don't care if ACK or any other TCP control bit is set at the
+same time.
+Let's see what happens to octet 13 when a TCP datagram
+with SYN-ACK set arrives:
+.PP
+.nf
+     |C|E|U|A|P|R|S|F|
+     |---------------|
+     |0 0 0 1 0 0 1 0|
+     |---------------|
+     |7 6 5 4 3 2 1 0|
+.fi
+.PP
+Now bits 1 and 4 are set in the 13th octet.
+The binary value of
+octet 13 is
+.IP
+     00010010
+.PP
+which translates to decimal
+.PP
+.nf
+   7     6     5     4     3     2     1     0
+0*2 + 0*2 + 0*2 + 1*2 + 0*2 + 0*2 + 1*2 + 0*2   = 18
+.fi
+.PP
+Now we can't just use 'tcp[13] == 18' in the \fItcpdump\fP filter
+expression, because that would select only those packets that have
+SYN-ACK set, but not those with only SYN set.
+Remember that we don't care
+if ACK or any other control bit is set as long as SYN is set.
+.PP
+In order to achieve our goal, we need to logically AND the
+binary value of octet 13 with some other value to preserve
+the SYN bit.
+We know that we want SYN to be set in any case,
+so we'll logically AND the value in the 13th octet with
+the binary value of a SYN:
+.PP
+.nf
+
+          00010010 SYN-ACK              00000010 SYN
+     AND  00000010 (we want SYN)   AND  00000010 (we want SYN)
+          --------                      --------
+     =    00000010                 =    00000010
+.fi
+.PP
+We see that this AND operation delivers the same result
+regardless whether ACK or another TCP control bit is set.
+The decimal representation of the AND value as well as
+the result of this operation is 2 (binary 00000010),
+so we know that for packets with SYN set the following
+relation must hold true:
+.IP
+( ( value of octet 13 ) AND ( 2 ) ) == ( 2 )
+.PP
+This points us to the \fItcpdump\fP filter expression
+.RS
+.B
+     tcpdump -i xl0 'tcp[13] & 2 == 2'
+.RE
+.PP
+Note that you should use single quotes or a backslash
+in the expression to hide the AND ('&') special character
+from the shell.

 .HD
 .B
 UDP Packets
 .HD
 .B
 UDP Packets


@@ -892,7 +1688,8 @@ UDP format is illustrated by this rwho packet:
 .RE
 This says that port \fIwho\fP on host \fIactinide\fP sent a udp
 datagram to port \fIwho\fP on host \fIbroadcast\fP, the Internet
 .RE
 This says that port \fIwho\fP on host \fIactinide\fP sent a udp
 datagram to port \fIwho\fP on host \fIbroadcast\fP, the Internet

-broadcast address.  The packet contained 84 bytes of user data.
+broadcast address.
+The packet contained 84 bytes of user data.

 .LP
 Some UDP services are recognized (from the source or destination
 port number) and the higher level protocol information printed.
 .LP
 Some UDP services are recognized (from the source or destination
 port number) and the higher level protocol information printed.


@@ -902,7 +1699,8 @@ RPC calls (RFC-1050) to NFS.
 UDP Name Server Requests
 .LP
 \fI(N.B.:The following description assumes familiarity with
 UDP Name Server Requests
 .LP
 \fI(N.B.:The following description assumes familiarity with

-the Domain Service protocol described in RFC-1035.  If you are not familiar
+the Domain Service protocol described in RFC-1035.
+If you are not familiar

 with the protocol, the following description will appear to be written
 in greek.)\fP
 .LP
 with the protocol, the following description will appear to be written
 in greek.)\fP
 .LP


@@ -912,24 +1710,29 @@ Name server requests are formatted as
 .sp .5
 \fIsrc > dst: id op? flags qtype qclass name (len)\fP
 .sp .5
 .sp .5
 \fIsrc > dst: id op? flags qtype qclass name (len)\fP
 .sp .5

-\f(CWh2opolo.1538 > helios.domain: 3+ A? ucbvax.berkeley.edu. (37)\fP
+\f(CWh2opolo.1538 > helios.domain: 3+ A? ucbvax.berkeley.edu. (37)\fR

 .sp .5
 .fi
 .RE
 Host \fIh2opolo\fP asked the domain server on \fIhelios\fP for an
 address record (qtype=A) associated with the name \fIucbvax.berkeley.edu.\fP
 .sp .5
 .fi
 .RE
 Host \fIh2opolo\fP asked the domain server on \fIhelios\fP for an
 address record (qtype=A) associated with the name \fIucbvax.berkeley.edu.\fP

-The query id was `3'.  The `+' indicates the \fIrecursion desired\fP flag
-was set.  The query length was 37 bytes, not including the UDP and
-IP protocol headers.  The query operation was the normal one, \fIQuery\fP,
-so the op field was omitted.  If the op had been anything else, it would
+The query id was `3'.
+The `+' indicates the \fIrecursion desired\fP flag
+was set.
+The query length was 37 bytes, not including the UDP and
+IP protocol headers.
+The query operation was the normal one, \fIQuery\fP,
+so the op field was omitted.
+If the op had been anything else, it would

 have been printed between the `3' and the `+'.
 Similarly, the qclass was the normal one,
 have been printed between the `3' and the `+'.
 Similarly, the qclass was the normal one,

-\fIC_IN\fP, and omitted.  Any other qclass would have been printed
+\fIC_IN\fP, and omitted.
+Any other qclass would have been printed

 immediately after the `A'.
 .LP
 A few anomalies are checked and may result in extra fields enclosed in
 immediately after the `A'.
 .LP
 A few anomalies are checked and may result in extra fields enclosed in

-square brackets:  If a query contains an answer, name server or
-authority section,
+square brackets:  If a query contains an answer, authority records or
+additional records section,

 .IR ancount ,
 .IR nscount ,
 or
 .IR ancount ,
 .IR nscount ,
 or


@@ -949,53 +1752,64 @@ Name server responses are formatted as
 \fIsrc > dst:  id op rcode flags a/n/au type class data (len)\fP
 .sp .5
 \f(CWhelios.domain > h2opolo.1538: 3 3/3/7 A 128.32.137.3 (273)
 \fIsrc > dst:  id op rcode flags a/n/au type class data (len)\fP
 .sp .5
 \f(CWhelios.domain > h2opolo.1538: 3 3/3/7 A 128.32.137.3 (273)

-helios.domain > h2opolo.1537: 2 NXDomain* 0/1/0 (97)\fP
+helios.domain > h2opolo.1537: 2 NXDomain* 0/1/0 (97)\fR

 .sp .5
 .fi
 .RE
 In the first example, \fIhelios\fP responds to query id 3 from \fIh2opolo\fP
 .sp .5
 .fi
 .RE
 In the first example, \fIhelios\fP responds to query id 3 from \fIh2opolo\fP

-with 3 answer records, 3 name server records and 7 authority records.
+with 3 answer records, 3 name server records and 7 additional records.

 The first answer record is type A (address) and its data is internet
 The first answer record is type A (address) and its data is internet

-address 128.32.137.3.  The total size of the response was 273 bytes,
-excluding UDP and IP headers.  The op (Query) and response code
+address 128.32.137.3.
+The total size of the response was 273 bytes,
+excluding UDP and IP headers.
+The op (Query) and response code

 (NoError) were omitted, as was the class (C_IN) of the A record.
 .LP
 In the second example, \fIhelios\fP responds to query 2 with a
 response code of non-existent domain (NXDomain) with no answers,
 (NoError) were omitted, as was the class (C_IN) of the A record.
 .LP
 In the second example, \fIhelios\fP responds to query 2 with a
 response code of non-existent domain (NXDomain) with no answers,

-one name server and no authority records.  The `*' indicates that
-the \fIauthoritative answer\fP bit was set.  Since there were no
+one name server and no authority records.
+The `*' indicates that
+the \fIauthoritative answer\fP bit was set.
+Since there were no

 answers, no type, class or data were printed.
 .LP
 Other flag characters that might appear are `\-' (recursion available,
 answers, no type, class or data were printed.
 .LP
 Other flag characters that might appear are `\-' (recursion available,

-RA, \fInot\fP set) and `|' (truncated message, TC, set).  If the
+RA, \fInot\fP set) and `|' (truncated message, TC, set).
+If the

 `question' section doesn't contain exactly one entry, `[\fIn\fPq]'
 is printed.
 .LP
 Note that name server requests and responses tend to be large and the
 default \fIsnaplen\fP of 68 bytes may not capture enough of the packet
 `question' section doesn't contain exactly one entry, `[\fIn\fPq]'
 is printed.
 .LP
 Note that name server requests and responses tend to be large and the
 default \fIsnaplen\fP of 68 bytes may not capture enough of the packet

-to print.  Use the \fB\-s\fP flag to increase the snaplen if you
-need to seriously investigate name server traffic.  `\fB\-s 128\fP'
+to print.
+Use the \fB\-s\fP flag to increase the snaplen if you
+need to seriously investigate name server traffic.
+`\fB\-s 128\fP'

 has worked well for me.
 
 .HD
 SMB/CIFS decoding
 .LP
 has worked well for me.
 
 .HD
 SMB/CIFS decoding
 .LP

-tcpdump now includes fairly extensive SMB/CIFS/NBT decoding for data
-on UDP/137, UDP/138 and TCP/139. Some primitive decoding of IPX and
-NetBEUI SMB data is also done. 
+\fItcpdump\fP now includes fairly extensive SMB/CIFS/NBT decoding for data
+on UDP/137, UDP/138 and TCP/139.
+Some primitive decoding of IPX and
+NetBEUI SMB data is also done.

 
 By default a fairly minimal decode is done, with a much more detailed
 
 By default a fairly minimal decode is done, with a much more detailed

-decode done if -v is used. Be warned that with -v a single SMB packet
+decode done if -v is used.
+Be warned that with -v a single SMB packet

 may take up a page or more, so only use -v if you really want all the
 gory details.
 
 If you are decoding SMB sessions containing unicode strings then you
 may take up a page or more, so only use -v if you really want all the
 gory details.
 
 If you are decoding SMB sessions containing unicode strings then you

-may wish to set the environment variable USE_UNICODE to 1. A patch to
-auto-detect unicode srings would be welcome.
+may wish to set the environment variable USE_UNICODE to 1.
+A patch to
+auto-detect unicode strings would be welcome.

 
 For information on SMB packet formats and what all te fields mean see
 
 For information on SMB packet formats and what all te fields mean see

-www.cifs.org or the pub/samba/specs/ directory on your favourite
-samba.org mirror site. The SMB patches were written by Andrew Tridgell
+www.cifs.org or the pub/samba/specs/ directory on your favorite
+samba.org mirror site.
+The SMB patches were written by Andrew Tridgell

 ([email protected]).
 
 .HD
 ([email protected]).
 
 .HD


@@ -1015,14 +1829,16 @@ sushi.201b > wrl.nfs:
        144 lookup fh 9,74/4096.6878 "xcolors"
 wrl.nfs > sushi.201b:
        reply ok 128 lookup fh 9,74/4134.3150
        144 lookup fh 9,74/4096.6878 "xcolors"
 wrl.nfs > sushi.201b:
        reply ok 128 lookup fh 9,74/4134.3150

-\fP
+\fR

 .sp .5
 .fi
 .RE
 In the first line, host \fIsushi\fP sends a transaction with id \fI6709\fP
 to \fIwrl\fP (note that the number following the src host is a
 .sp .5
 .fi
 .RE
 In the first line, host \fIsushi\fP sends a transaction with id \fI6709\fP
 to \fIwrl\fP (note that the number following the src host is a

-transaction id, \fInot\fP the source port).  The request was 112 bytes,
-excluding the UDP and IP headers.  The operation was a \fIreadlink\fP
+transaction id, \fInot\fP the source port).
+The request was 112 bytes,
+excluding the UDP and IP headers.
+The operation was a \fIreadlink\fP

 (read symbolic link) on file handle (\fIfh\fP) 21,24/10.731657119.
 (If one is lucky, as in this case, the file handle can be interpreted
 as a major,minor device number pair, followed by the inode number and
 (read symbolic link) on file handle (\fIfh\fP) 21,24/10.731657119.
 (If one is lucky, as in this case, the file handle can be interpreted
 as a major,minor device number pair, followed by the inode number and


@@ -1030,8 +1846,10 @@ generation number.)
 \fIWrl\fP replies `ok' with the contents of the link.
 .LP
 In the third line, \fIsushi\fP asks \fIwrl\fP to lookup the name
 \fIWrl\fP replies `ok' with the contents of the link.
 .LP
 In the third line, \fIsushi\fP asks \fIwrl\fP to lookup the name

-`\fIxcolors\fP' in directory file 9,74/4096.6878.  Note that the data printed
-depends on the operation type.  The format is intended to be self
+`\fIxcolors\fP' in directory file 9,74/4096.6878.
+Note that the data printed
+depends on the operation type.
+The format is intended to be self

 explanatory if read in conjunction with
 an NFS protocol spec.
 .LP
 explanatory if read in conjunction with
 an NFS protocol spec.
 .LP


@@ -1049,14 +1867,16 @@ wrl.nfs > sushi.1372a:
 .sp .5
 .fi
 .RE
 .sp .5
 .fi
 .RE

-(\-v also prints the IP header TTL, ID, and fragmentation fields,
+(\-v also prints the IP header TTL, ID, length, and fragmentation fields,

 which have been omitted from this example.)  In the first line,
 \fIsushi\fP asks \fIwrl\fP to read 8192 bytes from file 21,11/12.195,
 which have been omitted from this example.)  In the first line,
 \fIsushi\fP asks \fIwrl\fP to read 8192 bytes from file 21,11/12.195,

-at byte offset 24576.  \fIWrl\fP replies `ok'; the packet shown on the
+at byte offset 24576.
+\fIWrl\fP replies `ok'; the packet shown on the

 second line is the first fragment of the reply, and hence is only 1472
 bytes long (the other bytes will follow in subsequent fragments, but
 these fragments do not have NFS or even UDP headers and so might not be
 second line is the first fragment of the reply, and hence is only 1472
 bytes long (the other bytes will follow in subsequent fragments, but
 these fragments do not have NFS or even UDP headers and so might not be

-printed, depending on the filter expression used).  Because the \-v flag
+printed, depending on the filter expression used).
+Because the \-v flag

 is given, some of the file attributes (which are returned in addition
 to the file data) are printed: the file type (``REG'', for regular file),
 the file mode (in octal), the uid and gid, and the file size.
 is given, some of the file attributes (which are returned in addition
 to the file data) are printed: the file type (``REG'', for regular file),
 the file mode (in octal), the uid and gid, and the file size.


@@ -1064,21 +1884,95 @@ the file mode (in octal), the uid and gid, and the file size.
 If the \-v flag is given more than once, even more details are printed.
 .LP
 Note that NFS requests are very large and much of the detail won't be printed
 If the \-v flag is given more than once, even more details are printed.
 .LP
 Note that NFS requests are very large and much of the detail won't be printed

-unless \fIsnaplen\fP is increased.  Try using `\fB\-s 192\fP' to watch
+unless \fIsnaplen\fP is increased.
+Try using `\fB\-s 192\fP' to watch

 NFS traffic.
 .LP
 NFS traffic.
 .LP

-NFS reply packets do not explicitly identify the RPC operation.  Instead,
+NFS reply packets do not explicitly identify the RPC operation.
+Instead,
+\fItcpdump\fP keeps track of ``recent'' requests, and matches them to the
+replies using the transaction ID.
+If a reply does not closely follow the
+corresponding request, it might not be parsable.
+.HD
+AFS Requests and Replies
+.LP
+Transarc AFS (Andrew File System) requests and replies are printed
+as:
+.HD
+.RS
+.nf
+.sp .5
+\fIsrc.sport > dst.dport: rx packet-type\fP
+\fIsrc.sport > dst.dport: rx packet-type service call call-name args\fP
+\fIsrc.sport > dst.dport: rx packet-type service reply call-name args\fP
+.sp .5
+\f(CW
+elvis.7001 > pike.afsfs:
+       rx data fs call rename old fid 536876964/1/1 ".newsrc.new"
+       new fid 536876964/1/1 ".newsrc"
+pike.afsfs > elvis.7001: rx data fs reply rename
+\fR
+.sp .5
+.fi
+.RE
+In the first line, host elvis sends a RX packet to pike.
+This was
+a RX data packet to the fs (fileserver) service, and is the start of
+an RPC call.
+The RPC call was a rename, with the old directory file id
+of 536876964/1/1 and an old filename of `.newsrc.new', and a new directory
+file id of 536876964/1/1 and a new filename of `.newsrc'.
+The host pike
+responds with a RPC reply to the rename call (which was successful, because
+it was a data packet and not an abort packet).
+.LP
+In general, all AFS RPCs are decoded at least by RPC call name.
+Most
+AFS RPCs have at least some of the arguments decoded (generally only
+the `interesting' arguments, for some definition of interesting).
+.LP
+The format is intended to be self-describing, but it will probably
+not be useful to people who are not familiar with the workings of
+AFS and RX.
+.LP
+If the -v (verbose) flag is given twice, acknowledgement packets and
+additional header information is printed, such as the the RX call ID,
+call number, sequence number, serial number, and the RX packet flags.
+.LP
+If the -v flag is given twice, additional information is printed,
+such as the the RX call ID, serial number, and the RX packet flags.
+The MTU negotiation information is also printed from RX ack packets.
+.LP
+If the -v flag is given three times, the security index and service id
+are printed.
+.LP
+Error codes are printed for abort packets, with the exception of Ubik
+beacon packets (because abort packets are used to signify a yes vote
+for the Ubik protocol).
+.LP
+Note that AFS requests are very large and many of the arguments won't
+be printed unless \fIsnaplen\fP is increased.
+Try using `\fB-s 256\fP'
+to watch AFS traffic.
+.LP
+AFS reply packets do not explicitly identify the RPC operation.
+Instead,

 \fItcpdump\fP keeps track of ``recent'' requests, and matches them to the
 \fItcpdump\fP keeps track of ``recent'' requests, and matches them to the

-replies using the transaction ID.  If a reply does not closely follow the
+replies using the call number and service ID.
+If a reply does not closely
+follow the

 corresponding request, it might not be parsable.
 corresponding request, it might not be parsable.

+

 .HD
 .HD

-KIP Appletalk (DDP in UDP)
+KIP AppleTalk (DDP in UDP)

 .LP
 .LP

-Appletalk DDP packets encapsulated in UDP datagrams are de-encapsulated
+AppleTalk DDP packets encapsulated in UDP datagrams are de-encapsulated

 and dumped as DDP packets (i.e., all the UDP header information is
 and dumped as DDP packets (i.e., all the UDP header information is

-discarded).  The file
+discarded).
+The file

 .I /etc/atalk.names
 .I /etc/atalk.names

-is used to translate appletalk net and node numbers to names.
+is used to translate AppleTalk net and node numbers to names.

 Lines in this file have the form
 .RS
 .nf
 Lines in this file have the form
 .RS
 .nf


@@ -1087,11 +1981,12 @@ Lines in this file have the form
 
 \f(CW1.254             ether
 16.1           icsd-net
 
 \f(CW1.254             ether
 16.1           icsd-net

-1.254.110      ace\fP
+1.254.110      ace\fR

 .sp .5
 .fi
 .RE
 .sp .5
 .fi
 .RE

-The first two lines give the names of appletalk networks.  The third
+The first two lines give the names of AppleTalk networks.
+The third

 line gives the name of a particular host (a host is distinguished
 from a net by the 3rd octet in the number \-
 a net number \fImust\fP have two octets and a host number \fImust\fP
 line gives the name of a particular host (a host is distinguished
 from a net by the 3rd octet in the number \-
 a net number \fImust\fP have two octets and a host number \fImust\fP


@@ -1102,7 +1997,7 @@ The
 file may contain blank lines or comment lines (lines starting with
 a `#').
 .LP
 file may contain blank lines or comment lines (lines starting with
 a `#').
 .LP

-Appletalk addresses are printed in the form
+AppleTalk addresses are printed in the form

 .RS
 .nf
 .sp .5
 .RS
 .nf
 .sp .5


@@ -1110,25 +2005,27 @@ Appletalk addresses are printed in the form
 
 \f(CW144.1.209.2 > icsd-net.112.220
 office.2 > icsd-net.112.220
 
 \f(CW144.1.209.2 > icsd-net.112.220
 office.2 > icsd-net.112.220

-jssmag.149.235 > icsd-net.2\fP
+jssmag.149.235 > icsd-net.2\fR

 .sp .5
 .fi
 .RE
 (If the
 .I /etc/atalk.names
 .sp .5
 .fi
 .RE
 (If the
 .I /etc/atalk.names

-doesn't exist or doesn't contain an entry for some appletalk
+doesn't exist or doesn't contain an entry for some AppleTalk

 host/net number, addresses are printed in numeric form.)
 In the first example, NBP (DDP port 2) on net 144.1 node 209
 is sending to whatever is listening on port 220 of net icsd node 112.
 The second line is the same except the full name of the source node
 host/net number, addresses are printed in numeric form.)
 In the first example, NBP (DDP port 2) on net 144.1 node 209
 is sending to whatever is listening on port 220 of net icsd node 112.
 The second line is the same except the full name of the source node

-is known (`office').  The third line is a send from port 235 on
+is known (`office').
+The third line is a send from port 235 on

 net jssmag node 149 to broadcast on the icsd-net NBP port (note that
 the broadcast address (255) is indicated by a net name with no host
 number \- for this reason it's a good idea to keep node names and
 net names distinct in /etc/atalk.names).
 .LP
 net jssmag node 149 to broadcast on the icsd-net NBP port (note that
 the broadcast address (255) is indicated by a net name with no host
 number \- for this reason it's a good idea to keep node names and
 net names distinct in /etc/atalk.names).
 .LP

-NBP (name binding protocol) and ATP (Appletalk transaction protocol)
-packets have their contents interpreted.  Other protocols just dump
+NBP (name binding protocol) and ATP (AppleTalk transaction protocol)
+packets have their contents interpreted.
+Other protocols just dump

 the protocol name (or number if no name is registered for the
 protocol) and packet size.
 
 the protocol name (or number if no name is registered for the
 protocol) and packet size.
 


@@ -1138,15 +2035,17 @@ protocol) and packet size.
 .sp .5
 \s-2\f(CWicsd-net.112.220 > jssmag.2: nbp-lkup 190: "=:LaserWriter@*"
 jssmag.209.2 > icsd-net.112.220: nbp-reply 190: "RM1140:LaserWriter@*" 250
 .sp .5
 \s-2\f(CWicsd-net.112.220 > jssmag.2: nbp-lkup 190: "=:LaserWriter@*"
 jssmag.209.2 > icsd-net.112.220: nbp-reply 190: "RM1140:LaserWriter@*" 250

-techpit.2 > icsd-net.112.220: nbp-reply 190: "techpit:LaserWriter@*" 186\fP\s+2
+techpit.2 > icsd-net.112.220: nbp-reply 190: "techpit:LaserWriter@*" 186\fR\s+2

 .sp .5
 .fi
 .RE
 The first line is a name lookup request for laserwriters sent by net icsd host
 .sp .5
 .fi
 .RE
 The first line is a name lookup request for laserwriters sent by net icsd host

-112 and broadcast on net jssmag.  The nbp id for the lookup is 190.
+112 and broadcast on net jssmag.
+The nbp id for the lookup is 190.

 The second line shows a reply for this request (note that it has the
 same id) from host jssmag.209 saying that it has a laserwriter
 The second line shows a reply for this request (note that it has the
 same id) from host jssmag.209 saying that it has a laserwriter

-resource named "RM1140" registered on port 250.  The third line is
+resource named "RM1140" registered on port 250.
+The third line is

 another reply to the same request saying host techpit has laserwriter
 "techpit" registered on port 186.
 
 another reply to the same request saying host techpit has laserwriter
 "techpit" registered on port 186.
 


@@ -1167,23 +2066,29 @@ jssmag.209.165 > helios.132: atp-req  12266<3,5> 0xae030001
 helios.132 > jssmag.209.165: atp-resp 12266:3 (512) 0xae040000
 helios.132 > jssmag.209.165: atp-resp 12266:5 (512) 0xae040000
 jssmag.209.165 > helios.132: atp-rel  12266<0-7> 0xae030001
 helios.132 > jssmag.209.165: atp-resp 12266:3 (512) 0xae040000
 helios.132 > jssmag.209.165: atp-resp 12266:5 (512) 0xae040000
 jssmag.209.165 > helios.132: atp-rel  12266<0-7> 0xae030001

-jssmag.209.133 > helios.132: atp-req* 12267<0-7> 0xae030002\fP\s+2
+jssmag.209.133 > helios.132: atp-req* 12267<0-7> 0xae030002\fR\s+2

 .sp .5
 .fi
 .RE
 Jssmag.209 initiates transaction id 12266 with host helios by requesting
 .sp .5
 .fi
 .RE
 Jssmag.209 initiates transaction id 12266 with host helios by requesting

-up to 8 packets (the `<0-7>').  The hex number at the end of the line
+up to 8 packets (the `<0-7>').
+The hex number at the end of the line

 is the value of the `userdata' field in the request.
 .LP
 is the value of the `userdata' field in the request.
 .LP

-Helios responds with 8 512-byte packets.  The `:digit' following the
+Helios responds with 8 512-byte packets.
+The `:digit' following the

 transaction id gives the packet sequence number in the transaction
 and the number in parens is the amount of data in the packet,
 transaction id gives the packet sequence number in the transaction
 and the number in parens is the amount of data in the packet,

-excluding the atp header.  The `*' on packet 7 indicates that the
+excluding the atp header.
+The `*' on packet 7 indicates that the

 EOM bit was set.
 .LP
 EOM bit was set.
 .LP

-Jssmag.209 then requests that packets 3 & 5 be retransmitted.  Helios
-resends them then jssmag.209 releases the transaction.  Finally,
-jssmag.209 initiates the next request.  The `*' on the request
+Jssmag.209 then requests that packets 3 & 5 be retransmitted.
+Helios
+resends them then jssmag.209 releases the transaction.
+Finally,
+jssmag.209 initiates the next request.
+The `*' on the request

 indicates that XO (`exactly once') was \fInot\fP set.
 
 .HD
 indicates that XO (`exactly once') was \fInot\fP set.
 
 .HD


@@ -1198,16 +2103,21 @@ Fragmented Internet datagrams are printed as
 .sp .5
 .fi
 .RE
 .sp .5
 .fi
 .RE

-(The first form indicates there are more fragments.  The second
+(The first form indicates there are more fragments.
+The second

 indicates this is the last fragment.)
 .LP
 indicates this is the last fragment.)
 .LP

-\fIId\fP is the fragment id.  \fISize\fP is the fragment
-size (in bytes) excluding the IP header.  \fIOffset\fP is this
+\fIId\fP is the fragment id.
+\fISize\fP is the fragment
+size (in bytes) excluding the IP header.
+\fIOffset\fP is this

 fragment's offset (in bytes) in the original datagram.
 .LP
 fragment's offset (in bytes) in the original datagram.
 .LP

-The fragment information is output for each fragment.  The first
+The fragment information is output for each fragment.
+The first

 fragment contains the higher level protocol header and the frag
 fragment contains the higher level protocol header and the frag

-info is printed after the protocol info.  Fragments
+info is printed after the protocol info.
+Fragments

 after the first contain no higher level protocol header and the
 frag info is printed after the source and destination addresses.
 For example, here is part of an ftp from arizona.edu to lbl-rtsg.arpa
 after the first contain no higher level protocol header and the
 frag info is printed after the source and destination addresses.
 For example, here is part of an ftp from arizona.edu to lbl-rtsg.arpa


@@ -1222,12 +2132,14 @@ rtsg.1170 > arizona.ftp-data: . ack 1536 win 2560\fP\s+2
 .fi
 .RE
 There are a couple of things to note here:  First, addresses in the
 .fi
 .RE
 There are a couple of things to note here:  First, addresses in the

-2nd line don't include port numbers.  This is because the TCP
+2nd line don't include port numbers.
+This is because the TCP

 protocol information is all in the first fragment and we have no idea
 what the port or sequence numbers are when we print the later fragments.
 Second, the tcp sequence information in the first line is printed as if there
 were 308 bytes of user data when, in fact, there are 512 bytes (308 in
 protocol information is all in the first fragment and we have no idea
 what the port or sequence numbers are when we print the later fragments.
 Second, the tcp sequence information in the first line is printed as if there
 were 308 bytes of user data when, in fact, there are 512 bytes (308 in

-the first frag and 204 in the second).  If you are looking for holes
+the first frag and 204 in the second).
+If you are looking for holes

 in the sequence space or trying to match up acks
 with packets, this can fool you.
 .LP
 in the sequence space or trying to match up acks
 with packets, this can fool you.
 .LP


@@ -1236,7 +2148,8 @@ trailing \fB(DF)\fP.
 .HD
 Timestamps
 .LP
 .HD
 Timestamps
 .LP

-By default, all output lines are preceded by a timestamp.  The timestamp
+By default, all output lines are preceded by a timestamp.
+The timestamp

 is the current clock time in the form
 .RS
 .nf
 is the current clock time in the form
 .RS
 .nf


@@ -1244,19 +2157,30 @@ is the current clock time in the form
 .fi
 .RE
 and is as accurate as the kernel's clock.
 .fi
 .RE
 and is as accurate as the kernel's clock.

-The timestamp reflects the time the kernel first saw the packet.  No attempt
+The timestamp reflects the time the kernel first saw the packet.
+No attempt

 is made to account for the time lag between when the
 ethernet interface removed the packet from the wire and when the kernel
 serviced the `new packet' interrupt.
 .SH "SEE ALSO"
 is made to account for the time lag between when the
 ethernet interface removed the packet from the wire and when the kernel
 serviced the `new packet' interrupt.
 .SH "SEE ALSO"

-traffic(1C), nit(4P), bpf(4), pcap(3)
+stty(1), pcap(3), bpf(4), nit(4P), pfconfig(8)

 .SH AUTHORS
 .SH AUTHORS

+The original authors are:
+.LP

 Van Jacobson,
 Craig Leres and
 Steven McCanne, all of the
 Lawrence Berkeley National Laboratory, University of California, Berkeley, CA.
 .LP
 Van Jacobson,
 Craig Leres and
 Steven McCanne, all of the
 Lawrence Berkeley National Laboratory, University of California, Berkeley, CA.
 .LP

-The current version is available via anonymous ftp:
+It is currently being maintained by tcpdump.org.
+.LP
+The current version is available via http:
+.LP
+.RS
+.I http://www.tcpdump.org/
+.RE
+.LP
+The original distribution is available via anonymous ftp:

 .LP
 .RS
 .I ftp://ftp.ee.lbl.gov/tcpdump.tar.Z
 .LP
 .RS
 .I ftp://ftp.ee.lbl.gov/tcpdump.tar.Z


@@ -1265,37 +2189,62 @@ The current version is available via anonymous ftp:
 IPv6/IPsec support is added by WIDE/KAME project.
 This program uses Eric Young's SSLeay library, under specific configuration.
 .SH BUGS
 IPv6/IPsec support is added by WIDE/KAME project.
 This program uses Eric Young's SSLeay library, under specific configuration.
 .SH BUGS

-Please send bug reports to [email protected].
+Please send problems, bugs, questions, desirable enhancements, etc. to:
+.LP
+.RS
[email protected]
+.RE
+.LP
+Please send source code contributions, etc. to:
+.LP
+.RS
[email protected]
+.RE

 .LP
 NIT doesn't let you watch your own outbound traffic, BPF will.
 We recommend that you use the latter.
 .LP
 .LP
 NIT doesn't let you watch your own outbound traffic, BPF will.
 We recommend that you use the latter.
 .LP

+On Linux systems with 2.0[.x] kernels:
+.IP
+packets on the loopback device will be seen twice;
+.IP
+packet filtering cannot be done in the kernel, so that all packets must
+be copied from the kernel in order to be filtered in user mode;
+.IP
+all of a packet, not just the part that's within the snapshot length,
+will be copied from the kernel (the 2.0[.x] packet capture mechanism, if
+asked to copy only part of a packet to userland, will not report the
+true length of the packet; this would cause most IP packets to get an
+error from
+.BR tcpdump );
+.IP
+capturing on some PPP devices won't work correctly.
+.LP
+We recommend that you upgrade to a 2.2 or later kernel.
+.LP

 Some attempt should be made to reassemble IP fragments or, at least
 to compute the right length for the higher level protocol.
 .LP
 Some attempt should be made to reassemble IP fragments or, at least
 to compute the right length for the higher level protocol.
 .LP

-Name server inverse queries are not dumped correctly: The (empty)
+Name server inverse queries are not dumped correctly: the (empty)

 question section is printed rather than real query in the answer
 question section is printed rather than real query in the answer

-section.  Some believe that inverse queries are themselves a bug and
-prefer to fix the program generating them rather than tcpdump.
-.LP
-Apple Ethertalk DDP packets could be dumped as easily as KIP DDP
-packets but aren't.
-Even if we were inclined to do anything to promote the use of
-Ethertalk (we aren't), LBL doesn't allow Ethertalk on any of its
-networks so we'd would have no way of testing this code.
+section.
+Some believe that inverse queries are themselves a bug and
+prefer to fix the program generating them rather than \fItcpdump\fP.

 .LP
 A packet trace that crosses a daylight savings time change will give
 skewed time stamps (the time change is ignored).
 .LP
 .LP
 A packet trace that crosses a daylight savings time change will give
 skewed time stamps (the time change is ignored).
 .LP

-Filters expressions that manipulate FDDI headers assume that all FDDI
-packets are encapsulated Ethernet packets.  This is true for IP, ARP,
-and DECNET Phase IV, but is not true for protocols such as ISO CLNS.
-Therefore, the filter may inadvertently accept certain packets that
-do not properly match the filter expression.
+Filter expressions on fields other than those in Token Ring headers will
+not correctly handle source-routed Token Ring packets.
+.LP
+Filter expressions on fields other than those in 802.11 headers will not
+correctly handle 802.11 data packets with both To DS and From DS set.

 .LP
 .BR "ip6 proto"
 should chase header chain, but at this moment it does not.
 .LP
 .BR "ip6 proto"
 should chase header chain, but at this moment it does not.

-.BR tcp
-or
-.BR udp
-should chase header chain too.
+.BR "ip6 protochain"
+is supplied for this behavior.
+.LP
+Arithmetic expression against transport layer headers, like \fBtcp[0]\fP,
+does not work against IPv6 packets.
+It only looks at IPv4 packets.