Can't see my server on the Internet

Internally it's working great but I'm unable to access my Windows 2003 Server Data Center Edition on the Internet. I Can't connect to remote desktop, see my IIS Server (which I set to use port 81 due to me using a cable modem).. I just can't figure out why I can't see this thing on the Internet, I have two nics one set to a 192.168 the other to dhcp and conencted to my cable modem, IIS is binded to the IP set by the cable modem (public).. I've run apache and not had problems before but not on Server 2003 it was on XP, so I don't know if thats the problem.. Any ideas??? Thanks Guys!

Some more info on my setup.. Chat with my ISP

Troy J > Thank you for contacting Adelphia's High Speed Internet Support. Please describe how I may assist you while I look into your account information and contact history.
marussell > Quick Question, is port 81 blocked going out?
Troy J > No, it should not be blocked.
marussell > Also, should I be able to use Remote Desktop Connection on a PC connected to my Cable Modem, for some reason I'm unable to connect to it from the internet, locally it works great.
Troy J > Yes. Are you running a router?
Troy J > Or a firewall?
marussell > I have a Win Server 2003 Machine connected to the Cable Modem, then another NIC with a 192.168 address connected to a hub.
marussell > I just can't see IIS, Remote Desktop, etc from a computer on the internet, locally it all works great. (I'm trying to connect to the adelphia 69.x.x.x IP)
Troy J > Is this on a PC connected to the Hub then?
marussell > No it's the Server connected to the Cable Modem.
Troy J > Do you have a firewall connected to that machine?
marussell > No
Troy J > You must make sure that the listening port is open and that everything is enabled on the PC correctly.
marussell > Can you see http://69.161.71.183:81 ?
Troy J > Is that the port you are using for the Remote Desktop?
marussell > No IIS
Troy J > The use of an IIS server would be against the Terms of Service which was agreed on when you signed up for your High Speed Internet service.
marussell > Ah. I understand.
marussell > Could you do me a favor and just ping 69.161.71.183 and see if it responds?
Troy J > No it does not.
marussell > Hmmm, I ping it locally and it's fine. So there's something keeping it from taking connections from the internet... So frustrating
marussell > Any ideas? (so I can use remote desktop
Troy J > It sounds as though something is blocking ping requests.
Troy J > Yes, you should be able to use Remote Desktop without a problem.
marussell > Hmm.. Thanks for the help I'll look into it more with the OS. Good to know it's not blocked.
Troy J > You're welcome. Is there anything else I can help you with?

Fixed it.. Basic Firewall in Routing.. Fixed.. Done.. Cool!