filling up UDP socket buffers like mad

[Charles Swiger]

On Mar 24, 2006, at 4:17 PM, Michael W. Lucas wrote:
> Running FreeBSD 6.1-PRERELEASE as a DNS, dhcp, and syslog server.
>
> I'm having trouble with DNS, DHCP, and syslogd locking up, and I think
> I've found what they all share in common.
>
> During the lockups, the box starts dropping UDP due to full socket
> buffers.  I have a dumb little script to capture the rate of drops
> over 5 seconds, and it's about 45 a second.
>
> 168725 dropped due to full socket buffers
> 168958 dropped due to full socket buffers

There is generally a cause behind the socket buffers filling up,  
whether that is some form of livelock due to an OS problem or a  
misconfiguration with a firewall/dummynet setup.  You could look at  
the output of "netstat -a(n)" for insight as to where the packets are  
being queued up, but "netstat -s" would be useful to show to us as well.

-- 
-Chuck