then what i shall do??
there is option to make alias that means
www.domain.com is 10.0.0.3:80 from lan
Easiest way is to put
10.0.0.3
www.domain.comin your PCs hosts file.
Or you can enable DNS forwarder in m0n0wall and add the overide record there. In order for this to work, your PCs must use m0n0wall as the DNS forwarder.