Instability?

[Alex Moen]

Hello all,

I have a fairly complex server running, version 4.1.0 on Solaris 10 (I  
know, 4.1.1 is out, but I didn't see anything in the release notes  
about this problem).  Each of the 40-some config files is allowing  
clients based on VCI and vlan.  There are many requests that are  
denied because the VCI does not match, which is very much expected, so  
there are many "No free leases" entries in the log file.  This  
situation arises because this server is serving the networks for our  
IPTV set top boxes, and we only allow set top boxes to get an address  
and deny all other devices (such as firewalls, PC's, etc.)  However,  
customers still plug devices into the video-only ethernet ports on the  
DSL modems and FTTP ONT's thinking that they can use these ports for  
Internet access.

I have noticed that the DHCP process becomes unpredictably  
unresponsive (is that proper grammer????).  I do not know if it is  
because of the number of denies.  I do know that during one of these  
unresponsive spells, tcpdump shows dhcp packets arriving at the  
server, but no responses leaving the server, and no log entries  
signifying the receipt of the requests by the DHCP process.  The  
server itself is still responsive, and not by any means locked up,  
it's just like the DHCP process takes a nap.  "ps -ef" shows that the  
process is still running.

I have checked other things, like disk space (not by any means full),  
processor load, memory availability, etc. Everything seems fine, and a  
restart of the process fires the server back up and it performs just  
fine.  It is not a busy server by any means, I have other DHCP servers  
running that are way busier (on similar hardware) that don't have a  
problem, but also do not deal with nearly as many denies.

What is the best way to troubleshoot this?

Thanks for any ideas,

Alex