use existing PGM decoder for UDP-encapsulated PGM

[tcpdump] / tcpdump.1.in

diff --git a/tcpdump.1.in b/tcpdump.1.in
index cb2fbdd378e9cd61378f2452acd1408359e7eda2..c2569db3c3843b81f25c13f2c1af56d2dc631d56 100644 (file)
--- a/tcpdump.1.in
+++ b/tcpdump.1.in
@@ -519,6 +519,7 @@ Currently known types are
 \fBaodv\fR (Ad-hoc On-demand Distance Vector protocol),
 \fBcarp\fR (Common Address Redundancy Protocol),
 \fBcnfp\fR (Cisco NetFlow protocol),
+\fBpgm\fR (Pragmatic General Multicast),
 \fBradius\fR (RADIUS),
 \fBrpc\fR (Remote Procedure Call),
 \fBrtp\fR (Real-Time Applications protocol),
@@ -530,6 +531,10 @@ Currently known types are
 \fBzmtp1\fR (ZeroMQ Message Transport Protocol 1.0)
 and
 \fBvxlan\fR (Virtual eXtensible Local Area Network).
+.IP
+Note that the \fBpgm\fR type above affects UDP interpretation only, the native
+PGM is always recognised as IP protocol 113 regardless. UDP-encapsulated PGM is
+often called "EPGM" or "PGM/UDP".
 .TP
 .B \-t
 \fIDon't\fP print a timestamp on each dump line.