Re: URGENT: hard to reproduce TCP EAGAIN issue, networking gurus please contact <david@wgn.net>

David (david@kalifornia.com)
Sun, 22 Nov 1998 18:30:23 GMT


Ok. A few people replied, here are snippets, please keep
<david@kalifornia.com> in the replies until vger catches up.

----------------
> In article
>> ok. time is becoming critical and i will need to reboot soon. this is a
>> mass invite to diagnose a very hard to uncover TCP bug.

> Looks like you ran out of free memory. Could you check with "free" if you
> haven't already rebooted? Also try pressing Shift-ScrollLock on the console
> and send the resulting output.

the machine has 192megs of ram, 80 megs were free, i was an hour and a
half flight time from the console.

> SUID bit lost from the ssh executable? Ssh should be SUID root.

ssh was suid.

> Works fine for me here. Maybe you need to increase
> /proc/sys/net/ipv4/ip_local_port_range?

changing 1024/4099 to 1024/16384 in this file magically fixed it.

================
factoids:

lots of free ram
lots of free cpu cyles
lots of free disk space
lots of free sockets (100 odd sockets in use)
/proc memory looks very similar to other machines. i.e. no suspicions

in short, nothing was apparent. it was simply broken. users couldn't do
-anything- wrt opening a socket. root could open a socket only if it was
bound under 1023. with netstat/proc reporting just a bit over one hundred
sockets in use, (4999-1024) should be leaving quite a bit more room. the
machine wasn't loaded, cpu was zilch, disk zilch, network zilch. inbound
connections worked just dandy. local ports gave eagain/eaccess.

i'd toss out the idea of a magic number being hit in the local port code.
any takers on this?

-d

-- 
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