Forward domain name to ip with masking, but still show extensions

[coldscooter]

I have bought a domain name to point to my hosting server. I'm forwarding it to the ip with masking. The problem is, now the url only shows the root domain name:

http://www.domainname.com

and i want to be able to show:

http://www.domainname.com/something

or

http://www.domainname.com/somethingelse

Could anyone advise?