clarify meaning of NFS port numbers in tcpdump.1

Update the text in the "NFS Requests and Replies" section to match the
changes made in commits 68fe98a, f3051bc and 29d83db, which make output
format different for UDP and TCP.

So long as the difference remains keep it documented and keep in mind
that even after it goes away the manpage should mention the change for
a while.

diff --git a/tcpdump.1.in b/tcpdump.1.in
index 1dc3ec175120fe3d2b76336f0f8c03ce5aac2301..ae1b501f88b2fa16fe1b4b3039be5ab0f694e2fe 100644 (file)
--- a/tcpdump.1.in
+++ b/tcpdump.1.in
@@ -22,7 +22,7 @@
 .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 .\"
-.TH TCPDUMP 1  "12 July 2012"
+.TH TCPDUMP 1  "13 December 2013"
 .SH NAME
 tcpdump \- dump traffic on a network
 .SH SYNOPSIS
@@ -1427,8 +1427,12 @@ wrl.nfs > sushi.201b:
 .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).
+to \fIwrl\fP.
+(Note that for UDP NFS packets the standard UDP header isn't printed and the
+number following the src host is a transaction id, \fInot\fP the source port.
+The example above represents UDP NFS traffic.
+For TCP NFS packets port numbers are printed as part of the standard TCP header
+and the transaction id is printed separately as "xid" field of the packet.)
 The request was 112 bytes,
 excluding the UDP and IP headers.
 The operation was a \fIreadlink\fP