Thanks for taking you time.
default m0n0 installation
PC on LAN: 192.168.100.20
When surfing (IE6) to http://www.auditmypc.com/freescan/scanoptions.asp
using this PC on LAN they can detect the internal adress to 192.168.100.20
Is it IE6 that encloses the internal address?
>>The Monowall exposes my internal ip adress (NAT address). A security risk?
> Unless you did some major modifications to your default m0n0
> installation (advanced routing, etc), I don't think m0n0wall's the
> thing that's exposing your internal NAT address. You're probably
> noticing it from your application level, where some applications
> enclose the detected IP at the application layer.
> IMHO, for the most part, if it is a private IP range (not internet
> routable), exposing it to the outside world usually isn't going to be
> much of a security risk. Although, I'm sure for a determined attacker
> just knowing your external IP is enough to wreak havoc.