httpd-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Chuck Murcko <ch...@n2k.com>
Subject Re: WWW Form Bug Report: "many http connections in FIN_WAIT_2 state" on SunOS 4.x (fwd)
Date Fri, 13 Dec 1996 16:33:07 GMT
No. We see 'em here under Irix and BSDI, too. They're from half-closed
connections (timeouts, probably). Apache closes the connect (sends a
FIN, and goes into FIN_WAIT_1), then gets an ACK from the browser, and
goes into FIN_WAIT_2. Unless a FIN is then received from the browser,
which Apache ACKs (and then goes into TIME_WAIT, which times out and
returns the connection to CLOSED state), it will sit in FIN_WAIT_2 forever
on many OS, which don't time this state out. This slowly eats away mbufs
and mbuf clusters until the system panics or needs a reboot.

Timeouts from FIN_WAIT_2 are suggested by Stevens as a solution, but are
not required by the TCP protocol definition. The real fix is for browsers
to handle passive close properly. Either one will do. A 2MSL timeout on
FIN_WAIT_2 would work, as well.

My sense is the timeouts from Apache driving this are from the shorter
keepalive timeouts more than from 'normal' ones. My sense is also that
there is one particular TCP stack/browser that exhibits this behavior,
but I don't have enough hard data to name names.

Rob Hartill liltingly intones:
> 
> 
> KeepAlive's ?
> 
> ----- Forwarded message from rindfuss-s@medea.wz-berlin.de -----
> 
> Message-Id: <199612131357.FAA06797@taz.hyperreal.com>
> From: rindfuss-s@medea.wz-berlin.de
> To: apache-bugs%apache.org@organic.com
> Date: Fri Dec 13  5:57:17 1996
> Subject: WWW Form Bug Report: "many http connections in FIN_WAIT_2 state" on SunOS 4.x
> 
> Submitter: rindfuss-s@medea.wz-berlin.de
> Operating system: SunOS 4.x, version: 
> Version of Apache Used: 1.2b1
> Extra Modules used: 
> URL exhibiting problem: 
> 
> Symptoms:
> --
> After having upgraded Apache to version 1.2b1 (on SunOS 4.1.4) netstat shows lots of
http connections in FIN_WAIT_2 tcp state which never go away. 
> --
> 
> Backtrace:
> --
> 
> --
> 
> ----- End of forwarded message from rindfuss-s@medea.wz-berlin.de -----
> 
> 

chuck
Chuck Murcko	N2K Inc.	Wayne PA	chuck@telebase.com
And now, on a lighter note:
Blessed are they who Go Around in Circles, for they Shall be Known as
Wheels.

Mime
View raw message