Re: ipv4 connection problems

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

:> anyone else is seeing this behavior.
:>=20
:> Peter
:
:Here's a tcpdump output of a 'telnet 0 80':
:
:07:21:41.872244 IP (tos 0x10, ttl  64, id 43935, offset 0, flags [none], le=
:ngth: 64) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,wscale 0,nop,nop,sackOK,nop,nop,time=
:stamp 251468000 0>
:07:21:44.868076 IP (tos 0x10, ttl  64, id 45093, offset 0, flags [none], le=
:...

    I haven't been able to reproduce this yet.  I think our best chance of
    figuring it out, unless Jeff has an 'aha' moment, is for you to purposefully
    core the kernel while you have a telnet in this state.  i.e. while the telnet
    is stuck in this state do a ctl-alt-esc and panic the kernel to get a core
    dump (assuming you have it setup so it can do core dumps).  You might also
    want to 'sysctl -w kern.sync_on_panic=0' before doing that to prevent the
    kernel from locking up trying to flush the buffer cache during the panics.

						-Matt

:ngth: 64) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,wscale 0,nop,nop,sackOK,nop,nop,time=
:stamp 251468300 0>
:07:21:48.068122 IP (tos 0x10, ttl  64, id 46299, offset 0, flags [none], le=
:ngth: 64) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,wscale 0,nop,nop,sackOK,nop,nop,time=
:stamp 251468620 0>
:07:21:51.268172 IP (tos 0x10, ttl  64, id 47481, offset 0, flags [none], le=
:ngth: 48) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,nop,sackOK>
:07:21:54.468226 IP (tos 0x10, ttl  64, id 48667, offset 0, flags [none], le=
:ngth: 48) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,nop,sackOK>
:07:21:57.668273 IP (tos 0x10, ttl  64, id 49811, offset 0, flags [none], le=
:ngth: 48) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,nop,sackOK>
:07:22:03.868365 IP (tos 0x10, ttl  64, id 52138, offset 0, flags [none], le=
:ngth: 48) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,nop,sackOK>
:07:22:16.068553 IP (tos 0x10, ttl  64, id 56963, offset 0, flags [none], le=
:ngth: 48) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,nop,sackOK>
:07:22:40.268914 IP (tos 0x10, ttl  64, id 64387, offset 0, flags [none], le=
:ngth: 48) 209.200.146.2.3828 > 209.200.146.2.80: S [tcp sum ok] 4209775517:=
:4209775517(0) win 57344 <mss 16344,nop,nop,sackOK>