Error 49, socket problem?

[gnn at FreeBSD.org]

At Tue, 12 Oct 2004 12:52:15 -0600,
Stephane Raimbault wrote:
> 
> I have some busy boxes part of a cluster which seems to occassionaly get an 
> Error 49 on various network based applications at the same time.
> 
> Here is from an apache proxy log
> 
> [Fri Oct 08 11:26:45 2004] [error] (49)Can't assign requested address: 
> proxy: HTTP: attempt to connect to 127.0.0.1:81 (127.0.0.1) failed
> [Fri Oct 08 11:26:45 2004] [error] (49)Can't assign requested address: 
> proxy: HTTP: attempt to connect to 127.0.0.1:81 (127.0.0.1) failed
> [Fri Oct 08 11:26:45 2004] [error] (49)Can't assign requested address: 
> proxy: HTTP: attempt to connect to 127.0.0.1:81 (127.0.0.1) failed
> [Fri Oct 08 11:26:46 2004] [error] (49)Can't assign requested address: 
> proxy: HTTP: attempt to connect to 127.0.0.1:81 (127.0.0.1) failed
> [Fri Oct 08 11:26:46 2004] [error] (49)Can't assign requested address: 
> proxy: HTTP: attempt to connect to 127.0.0.1:81 (127.0.0.1) failed
> 
> 
> Various other things at the same time give a similar error.  Am I running 
> out of sockets on the system?  What is the best way to diagnose this 
> problem.  It seems pretty intermitent, however it seems to occur when the 
> boxes are at some of the busiest moments in it's day.

That's the loopback address (127.0.0.1) and the error you're getting
is "Address Not Available" (/usr/include/sys/errno.h shows this).  I
have no idea what apahce is trying to do in that case, but you should
attempt to figure that out.

One theory is that this is some sort of external attack which puts the
loopback address into a URL to try and get apache to do something
"bad".  But, I'm not an apache expert.

Later,
George