pf traffic shaping and perfomance

Zbigniew Szalbot zszalbot at
Thu Apr 24 05:49:54 UTC 2008

Hi Luke,

On Wed, 23 Apr 2008 12:40:04 -0700 (PDT), Luke Dean <LukeD at>
> On Wed, 23 Apr 2008, Zbigniew Szalbot wrote:
>> Hello,
>> I would like to implement traffic shaping using pf. I know I need to
>> recompile kernel to be able to achieve this but I have a more general
>> question. I used to have pf with traffic shaping on a Pentium III 866
>> before and as soon as I activated it, the http response of the box was
>> noticably slower. Here are the defs I used then:
>> #altq on $ext_if cbq bandwidth 512Kb queue { def, smtp, udp, http, \
>> #ssh, icmp }
>> #queue def bandwidth 13% cbq(default borrow red)
>> #queue smtp bandwidth 25% cbq(borrow red) priority 7
>> #queue udp bandwidth 10% cbq(borrow red)
>> #queue http bandwidth 40% cbq(borrow red)
>> #queue ssh bandwidth 10% cbq(borrow red)
>> ##{ ssh_interactive, ssh_bulk }
>> ##queue ssh_interactive priority 7
>> #queue ssh_bulk priority 0
>> #queue icmp bandwidth 2% cbq
>> It is quite possible that I misconfigured the shaping (as seen above).
> What
>> would be suggested traffic shaping rules to allow smooth mail operation
>> (smtp taking up to 40% of allowed bandwidth) and http responses?
>> If that matters, uname -v
>> FreeBSD 7.0-RELEASE #0
>> Many thanks in advance!
> I had the same problem with class-based queueing when I tried this.  I
> suspect that the 512Kb in your initial queue definition is the limiting
> factor.  I never did get it to work like I expected it to, however, so
> maybe I just don't understand it.
> Eventually I realized that I didn't actually want to chop up my bandwidth
> like this.  What I really wanted to do was simply prioritize the traffic.
> The most important applications get first shot at the bandwidth, and the
> less important applications get choked when they need to be.  I switched
> to priority queueing and I've been very happy with it.

Thanks! That gives me a clue! Would you mind sharing your defs? I'll be
reading the man anyway.

Zbigniew Szalbot

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