this should work, but i dont know.
go into control panel > network connections > network bridge (network bridge) and go to status. there it gives you the IP of your computer. remember it. go into warcraft 3 > options > gameplay, and check to see what port it says. now open your internet browser and go to this site:
192.168.1.1 it will tell you to sign in, type in admin as the "account name" and admin as the password. go to advanced (its an orange tab). go to forwarding. here you type in WC3 in the boxes on the left, and you type in the port number that it says on WC3. it should look something like this:
ext port.
wc3 [5224] [5224] then you check both boxes if they arent, then you type in the IP address you have from the network bridges. then check the enable box, and you should be able to host.