Machine: FreeBSD 4.3
ipf: IP Filter: v3.4.20 (264)

First this bug may be resolved by me upgrading IPF. If that's the case
I'll just do that once informed :-) I haven't yet as I've not had and
problems.

One of my users tried to send a 'larger than normal' email today, and we
found it would hang at different point during the transmission (50%, 70%,
99%, etc). But with IPF disabled it wouldn't hang.

I watched him over tcpdump to see what was happening.. the output is at
the end of the email. I'm assuming that it has something to do with the
fragmented packets that he's sending? I don't have any rules in place that
block short, or block ipopts.

Thanks :)

213.x.x.x.33198 > 212.x.x.x.x.25: S 1202933080:1202933080(0) win 16384 <mss 
1460,nop,nop,sackOK>
212.x.x.x.x.25 > 213.x.x.x.33198: S 1822686022:1822686022(0) ack 1202933081 win 65535 
<mss 1460> (DF)
213.x.x.x.33198 > 212.x.x.x.x.25: . ack 1 win 17520
212.x.x.x.x.25 > 213.x.x.x.33198: P 1:52(51) ack 1 win 65535 (DF)
213.x.x.x.33198 > 212.x.x.x.x.25: P 1:15(14) ack 52 win 17469
212.x.x.x.x.25 > 213.x.x.x.33198: P 52:97(45) ack 15 win 65535 (DF)
213.x.x.x.33198 > 212.x.x.x.x.25: P 15:49(34) ack 97 win 17424
212.x.x.x.x.25 > 213.x.x.x.33198: P 97:105(8) ack 49 win 65535 (DF)
213.x.x.x.33198 > 212.x.x.x.x.25: P 49:81(32) ack 105 win 17416
212.x.x.x.x.25 > 213.x.x.x.33198: P 105:113(8) ack 81 win 65535 (DF)
213.x.x.x.33198 > 212.x.x.x.x.25: P 81:87(6) ack 113 win 17408
212.x.x.x.x.25 > 213.x.x.x.33198: P 113:127(14) ack 87 win 65535 (DF)
213.x.x.x.33198 > 212.x.x.x.x.25: . 87:1523(1436) ack 127 win 17394 (frag 8539:1456@0+)
213.x.x.x.33198 > 212.x.x.x.x.25: . 1547:2983(1436) ack 127 win 17394 (frag 
8540:1456@0+)
213.x.x.x.33198 > 212.x.x.x.x.25: . 3007:4443(1436) ack 127 win 17394 (frag 
8541:1456@0+)
213.x.x.x.33198 > 212.x.x.x.x.25: P 4467:5377(910) ack 127 win 17394
212.x.x.x.x.25 > 213.x.x.x.33198: . ack 87 win 65535 (DF)
213.x.x.x.33198 > 212.x.x.x.x.25: P 5377:5382(5) ack 127 win 17394
212.x.x.x.x.25 > 213.x.x.x.33198: . ack 87 win 65535 (DF)
213.x.x.x.33198 > 212.x.x.x.x.25: . 87:1523(1436) ack 127 win 17394 (frag 8544:1456@0+)
213.x.x.x.33198 > 212.x.x.x.x.25: . 87:1523(1436) ack 127 win 17394 (frag 8545:1456@0+)
213.x.x.x.33198 > 212.x.x.x.x.25: . 87:1523(1436) ack 127 win 17394 (frag 8547:1456@0+)
213.x.x.x.33198 > 212.x.x.x.x.25: . 87:1523(1436) ack 127 win 17394 (frag 8548:1456@0+)


-- 
Avleen Vig
Work Time: Unix Systems Administrator
Play Time: Network Security Officer
Smurf Amplifier Finding Executive: http://www.ircnetops.org/smurf


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