Bert Freudenberg wrote:
>>> Yes, iptables magic came to my mind, too. This would have very low 
>>> latency overhead, I doubt it would be measurable at all.
>>
>> Can iptables look at the content of a connection? The problem is that 
>> if a user is in a forum and another one tries to join him, they need 
>> to end up in the same image (at least right now). And we can't use 
>> different ports for this - we run through firewalls and NATs and all 
>> sorts of insane corporate IT setups so the choice of port is not 
>> completely ours.
> 
> 
> Yes, iptables can look at the packet contents, for example using the u32 
> module:
> 
>     http://www.stearns.org/doc/iptables-u32.current.html
> 
> You should ask a real expert of course, I never did this myself.

Ooooohhhhh. How useful. I think you just solved that problem for me.

Thanks,
   - Andreas