First, get a different ISP, seriously.  If that won't work for some 
reason, then put your m0n0wall on the public IP, and then put each of 
your PC's behind it on a LAN, having it provide DHCP for them.  If the 
ISP can somehow detect PCs behind the m0n0wall after that, I'm not 
certain what the technique is, but it may be that they can detect any 
NATing or routing you do from m0n0wall to PCs inside the LAN, so you may 
not be able to provide external services.  Experiment with blocking 
everything coming in (but not going out) and see if that works.

Also, make sure your ISP is really doing what you think they are doing.  
Have you talked to them, or are you just having problems with specific PCs?

Jeff

pcnet wrote:
> from a week now my isp does not alow more than 1 pc on lan how can i trick them? 
>
> they seem to know that i am routing the traffic what must i do to reuse the m0n0wall, that was
perfectly working?
>
> thanks in advance, grigore.
>
>