Hi tcpdump folks,
I've been writing a document explaining inside/outside fragmentation in
an OpenVPN context, explaining my points with "tcpdump", like this:
$ tcpdump -vv -i any host ... or host ...
11:43:48.930177 tun2 Out IP6 (flowlabel 0xa3885, hlim 64, next-header ICMPv6
(58) payload length: 1460) fd00:abcd:194:2::100c > fd00:abcd:194:2::1: [icmp6
sum ok] ICMP6, echo request, id 12415, seq 1
11:43:48.930293 enp3s0 Out IP (tos 0x0, ttl 64, id 3286, offset 0, flags [+],
proto UDP (17), length 1500)
193.149.48.143.44314 > 199.102.77.82.51194: UDP, length 1524
11:43:48.930303 enp3s0 Out IP (tos 0x0, ttl 64, id 3286, offset 1480, flags
[none], proto UDP (17), length 72)
193.149.48.143 > 199.102.77.82: ip-proto-17
(intentionally tunneling IPv4 over IPv6, to make it even more obvious
which is "inside" and which is "outside")
This is tcpdump 4.99.5 on gentoo linux.
What is very obvious here is that for IPv4, there is a clear indication
on the IPv4 packet length (in the first line printed per-packet) and
also the payload length (in the second line).
For IPv6, there is just one line, and no overall IPv6 packet length
printed whatsoever - and also, "just one line per packet", not the
two-line format.
This is... non-helpful trying to understand what happens on which layer.
So - if I were to send a patch to change IPv6 printing to be similar
to IPv4 (dual-line, and overall packet length) would this be something
you are interested in? Or is someone already working on it, per chance?
gert
--
"If was one thing all people took for granted, was conviction that if you
feed honest figures into a computer, honest figures come out. Never doubted
it myself till I met a computer with a sense of humor."
Robert A. Heinlein, The Moon is a Harsh Mistress
Gert Doering - Munich, Germany g...@greenie.muc.de
_______________________________________________
tcpdump-workers mailing list -- tcpdump-workers@lists.tcpdump.org
To unsubscribe send an email to tcpdump-workers-le...@lists.tcpdump.org
%(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s
