Re: router/gateway limit problems

[Steven Bellovin <smb%cs.columbia.edu@localhost>]

On Dec 30, 2009, at 12:17 AM, Chris Ross wrote:

> 
>  I have a netbsd-5 host running as my local router.  i386.  For quite a 
> while, during heavy traffic times, I'm seeing the following on the console:
> 
> Dec 30 00:14:04 router named[19459]: socket: too many open file descriptors
> 
>  Now, I'm sure there is some configurable parameter to either the kernel, or 
> named's environment that could alleviate this problem, but I've been unable 
> to figure it out so far.  This router is, as you'd guess, running a caching 
> nameserver and is the primary nameserver for all connected networks.
> 
>  Could anyone advise me?  Thanks.
> 
It's probably related to the security hack that's in named, to move queries 
around across a group of many different sockets.  I think that the best you can 
do is to increase the number of file descriptors available to named via a 
ulimit command.  What I do is have

        ulimit -n 256

in /etc/rc.conf.d/named, but you can (and probably should) go higher than 256.

                --Steve Bellovin, http://www.cs.columbia.edu/~smb