ethereal
has a cool little-known feature: the
-z
option
to generate statistics from a pcap file. For instance, here's how to
get a count of how much traffic you saw every five minutes:
$ tethereal -q -r foo.pcap -z io,stat,300
===========================================
IO Statistics
Interval: 300.000 secs
Column #0:
| Column #0
Time |frames| bytes
000.000-300.000 3832 344880
300.000-600.000 3744 336960
600.000-900.000 2316 208440
===========================================
The query language is pretty bizarre and protocol specific but there
are some useful analysis tools. There's also the
proto,colinfo option which lets you select out arbitrary
protocol columns to print in the text dump from tethereal.