ok, usually the problem can be at 3 points.
- your isp is blocking certain packets. but this is quite unlikely that they block such an obscure ports as a network game port for no big reason. so last part to doubt about.
- your router is blocking on certain packets. this can happen very likely, even stupid me got my router a bit too tight recently and those network game packets were blocked on the router and didn't pass through, thus when me and someone joined in a same game, the joining screen froze up when network couldn't reach each others.
- your machine is blocking those packets. this is also likely if you have some heavy security app going on in the back. i don't even have those apps running (since i know where virus can come from and i dont do those things and i usually know how to handle not to get caught and dont want machine to be so heavy and all) but you should ask someone who has the same app, or read some manual or something to loosen it a bit and just guard where you want it (like web browse, email etc) also make sure windows firewall is allowing homeworld2 and a few more entries related to directx for network communication as well.
i think, you should, for once, turn your security app and windows firewall completely off (no, you don't get infected just coz u turn it off... but do keep your machine up to date on applications, especially windows itself and generally watch out any file u download from the net unless it's from a trusted site) and see if hosting helps, if it does, then on, figure out how to make your security app /windows firewall a bit relaxing while doing the job. if it doesn't help at all, look at your router, the ports you need to forward are written at
hw2/ page. usually a router doesn't have crazy strict configuration but still, read manual see if there's anything to help loosen something if it's too tight. and make sure you do the port forwarding right, especially if your computer is assigned a dynamic dhcp from your router instead of statically assigned, your local ip can change if you reboot or router reboots, which can just screw the forwarding that is designated to a certain ip.
also, there are some people who just unplug router and get your comp straight to the modem and to the internet and that also seems to help quite a bit, if you want to... at least that removes the router portion of the problem for diagnose.