Subject: Re: Measuring dropped packets
To: None <tech-net@netbsd.org>
From: Manuel Bouyer <bouyer@antioche.eu.org>
List: tech-net
Date: 10/26/2006 15:14:33
On Thu, Oct 26, 2006 at 10:59:14AM +0200, Christoph Kaegi wrote:
>
> Hello List
>
> Our 3.0 ipf Firewall handles several thousand users on a 40MBit/s
> link to the internet.
>
> Now we experience delays on internet connections and certain
> applications (video conferencing) report packet loss.
>
> How can I find out if and where packets are dropped on the firewall?
> (apart from netstat -di)
Well, netstat -di can give a good hint already. But the wm driver
didn't properly report some inputs error, I fixed this recently in
current.
You can also look at netstat -q, to see if there are drops at a highter
level. If you see drops here you can try to bump IFQ_MAXLEN
to something larger than 256.
Also look at vmstat -m, especially for failed requests to mbpl and mclpl.
If there are failed requests you have to bump NMBCLUSTERS (you'll have to
if you bump IFQ_MAXLEN anyway, I think)
You may also want to install something like pkgsrc/net/mrtg, to
monitor traffic, in both byte count and packets counts (the script provided
in the above package does byte count, but it's trivial to change it to
do packets count too)
--
Manuel Bouyer <bouyer@antioche.eu.org>
NetBSD: 26 ans d'experience feront toujours la difference
--