Application layer classifier for ipfw

Mike Makonnen mtm at
Thu Jul 31 13:04:58 UTC 2008

Lawrence Stewart wrote:
> Hi Mike,
> Mike Makonnen wrote:
> [snip]
>> sharing applications which were hogging all the bandwidth. I looked 
>> for  programs that would allow me to shape traffic according to the 
>> application layer protocol, but couldn't find any for FreeBSD. I 
>> found a couple: l7-filter and ipp2p, but these are Linux specific. 
>> So, I decided to write one. The result is ipfw-classifyd :
> [snip]
> Unfortunately, I suspect you should have looked a bit harder: Bro 
> ( or Snort (, both of 
> which are in the FreeBSD ports tree, would have saved you from 
> reinventing the wheel.
I'm not sure they have the exact type of wheel I'm looking for :-). My 
understanding is that their primary function is Intrusion Detection, not 
traffic shaping. To use them as traffic shapers would require extra work 
on the sysadmin's part (scripts and other types of scotch tape). Am I 
wrong? The ipfw-classifyd daemon, on the other hand, works directly with 
ipfw(4). I suspect that for traffic shaping using ipfw-classifyd would 
require a lot less effort than using either of the above solutions. At 
the very least it's an additional tool in the FreeBSD sysadmin's arsenal.

BTW, my motivation for writing this program wasn't because there were no 
other tools that did this (as I mentioned I had already found Linux 
tools that would do this), but because I wanted a solution that uses 
FreeBSD and is BSD licensed :-)


Mike Makonnen       | GPG-KEY:
mtm @ FreeBSD.Org   | AC7B 5672 2D11 F4D0 EBF8  5279 5359 2B82 7CD4 1F55
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