Re: Explicit source port mapping

[Andreas Micklei <andreas.micklei@ivistar.de>]

Am Mittwoch, 1. November 2006 16:48 schrieben Sie:
> I've never heard about such a feature.
>
> Just a simple question :
> 	Why do you want to do this ?

We are deploying netfilter in a research project for a customer. He wants to 
be able to distinguish natted hosts on the WAN side for traceability.

Just don't ask further. ;-)

So if no one has ever implemented that: Where do I start? Where is the 
implicit source port mapping done (the one to avoid clashes) and can I hook 
into this mechnism with a kernel module, or should I modify the existing 
kernel code (which I have not looked at -  yet)?

> BR,
>
> Le mercredi 01 novembre 2006 à 16:24 +0100, Andreas Micklei a écrit :
> > Greetings,
> >
> > I have an unusual (maybe?) request. I have several private IPs
> > (192.168.x.x) behind a Linux gateway. All are NATed to the Internet. Now
> > I want to explicitely map each private IP to a fixed source port range on
> > the WAN interface of the gateway.
> >
> > Example:
> >
> > Connections from 192.168.42.1 are mapped to source ports 1024 - 1279
> > Connections from 192.168.42.2 are mapped to source ports 1280 - 1343
> > Connections from 192.168.42.3 are mapped to source ports 1344 - 1408
> > ...
> >
> > Quetions 1: Can netfilter do this for me?
> > Question 2: If not, would it be easy to implement, and can someone give a
> > suggestion where I should start? - Or even better: Has someone already
> > implemented this?
> >
> > Sorry if my question sounds stupid. In the HOWTOs I could only find
> > implicit source port mapping. Also I did not find a search interface for
> > the mailinglist. So if this question is already answered, pointers are
> > appreciated.
> >
> > regards,
> > Andreas Micklei