Error 49, socket problem?

[gnn at FreeBSD.org]

At Wed, 13 Oct 2004 09:36:03 -0600,
Stephane Raimbault wrote:
> 
> I doubt it's a DoS attack, however it could very well be.
> 

Well, probably not, given what you told us below.

> In this particular setup, apache runs on port 80 and 81.  A slimed down 
> version of apache handles basic http requests on port 80 and on port 81, we 
> have a beefier version of apache with php running applications.  We proxy 
> the request from port 80 to port 81 so the client only ever sees connections 
> to port 80.
> 
> What I find strange is other applications on the server freak out when this 
> is happening in the same manner.  such as php not able to make mysql 
> connections with a similar error.  The errors aren't limited to 127.0.0.1 
> either, it seems to be an overall problem with the box, not specifically the 
> loopback or apache.
> 
> PHP Warning:  mysql_connect(): Can't connect to MySQL server on 
> 'dbm.xxx.xxx.com' (49) in /www/index.php on line 4060
> 
> In this case the above dbm.xxx.xxx.com resolves to 10.0.12.22 which is one 
> of the MySQL server's in the cluster.
> 
> I've ruled out that it's a problem with the MySQL server in this case, 
> because I have 4 other web servers (running apache) able to connect to that 
> MySQL server during the same time.  All web servers in this cluster seem to 
> exhibit the error randomly at diffrent times.  Not only during high peak 
> traffic times as previously thought.
> 
> Are there buffers I could be running out of?  What should I be checking?  
> Perhaps something in sysctl...  If I know what I should probably be looking 
> at, I can probably monitor and have certain variables logged / graphed for a 
> better idea of what is going on.
> 

What version of FreeBSD are you running?

I would check the interfaces (ifconfig -a), routing table (netstat
-rn), and then the rest of the network statistics (man netstat) when
this happens.    Does it happen reliably or intermittently?

Later,
George