FreeBSD Traffic Shaping

The-IRC Hosting Administration Team Admin at The-IRC.Org
Wed Apr 2 04:12:15 UTC 2008

I have personally tried that before and it did not worked as described, in
fact it didn't work at all to limit anything on FBSD6.

-----Original Message-----
From: owner-freebsd-questions at
[mailto:owner-freebsd-questions at] On Behalf Of Christopher Cowart
Sent: Tuesday, April 01, 2008 7:55 PM
To: freebsd at
Cc: freebsd-questions at
Subject: Re: FreeBSD Traffic Shaping

freebsd at wrote:
> I am trying to limit the bandwidth available to some connections and 
> I'm not sure FreeBSD can handle this. Maybe some of you can help. 
> Here's what I need to have exactly.
> No matter what the number of connections, each connection should have 
> at most/least 50kbps guaranteed outbound on port 80.
> I've tried dummynet but it doesn't do what I need because if I define 
> a pipe with 1mbps and if I have 1000 connections, each connection will 
> have less than 50kbps.
> Any way to do this in FreeBSD ?

The ipfw(8) man page describes a "mask" configuration parameter.

# /sbin/ipfw pipe 1 config mask src-ip 0xffffffff bw 56Kbit/s

This creates a separate dynamic pipe per source ip address. Each pipe has a
dedicated 56kbps. The man page implies that the mask can combine fields, so
to uniquely identify "each connection", you would mask all bits of source
and destination IP and ports. It looks like the "all"
keyword might do just the trick.

Chris Cowart
Network Technical Lead
Network & Infrastructure Services, RSSP-IT UC Berkeley

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