internet slowdown

[Bill Moran]

In response to prad <prad at towardsfreedom.com>:

> we have 2 freebsd7 servers using pf with static ip addresses through
> our cable company (shaw cable) connecting our internal network to the
> outside. the servers do websites, email and nameserve (bind94)
> 
> sometimes one or both become sluggish letting us connect to websites.
> the ping times become 10+ times as long.
> pinging the servers from the outside also slows down.
> 
> whenever we reboot the servers, everything is fine again for several
> hours and then the speed starts fluctuating and then eventually
> everything slows down again. (however the several hours is not certain
> either because i just rebooted and everything slowed down after a few
> minutes this time).
> 
> i tried /etc/netstart and that speeded things up for a few pings only.
> doing a systat shows the cpu to be idle more than 90% of the time.
> we are presently trying to figure out netstat.
> 
> we never experienced this issue with freebsd 6.3 which we ran for
> several months. we've run freebsd7 since the beginning of june and this
> problem seemed to start showing up within the first week.
> 
> i am not sure where to look in order to solve this problem -
> specifically which log files might provide some clues regarding the net.
> 
> suggestions please?

Is the console responsive when this happens?  It doesn't sound like a
CPU issue to me -- ICMP messages are low enough CPU overhead that the
system would have to be pretty badly bogged for CPU starvation to cause
problems.

What do your network traffic graphs show during the slowdowns?  Perhaps
some sort of network flood occurring?

-- 
Bill Moran
http://www.potentialtech.com