From: Windows Vista Help: Allow a program to communicate through Windows Firewall
By default, most programs are blocked by Windows Firewall, to help make your computer more secure. To work properly, some programs might require you to allow them to communicate through the firewall. Here's how to do that:
1. Open Windows Firewall by clicking the Start button Picture of the Start button, clicking Control Panel, clicking Security, and then clicking Windows Firewall.
2. In the left pane, click Allow a program through Windows Firewall. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
3. Select the check box next to the program you want to allow, and then click OK.
It's most likely to do with your rounter or your internet modem. What type of internet do you have?I cant host games but i can join games fine with out lag. I tryed the sticky high lat thign on here but it didnt work i dont know if its becus im on vista or wut but plz help me out
Yes, post it on all of those sites and maybe one person may be able to provide an answer.The problem could be that you have a router. However, there is a way to fix the problem by forwarding your ports. If you have a "Linksys WRT110" router, then click here. If you have a different router, then click here. If neither of those solutions worked, then I recommend you post your tech support problem on several different forums (I recommend you post it on the SS Free, Forum Unity, WarBoards, Trollz, Explosmertacular, the new Battle.net forums, the old Battle.net forums, StarEdit Network, Maplantis, BlizzForums, Creep Colony, BattleReports, Godz Minnionz, StarCraft.org, Battle Forums, Reenactor Entertainment, Facepunch Studios, Lethal Injection, StarCraft Meetup, and D3Scene.ru) and I also recommend you contact Blizzard Entertainment. To contact Blizzard Entertainment you can e-mail "firstname.lastname@example.org" (without the quotation marks), call "(949) 955-1382", go to the channel "Blizzard Tech Support" (without the quotation marks) on the U.S. West gateway, or send them mail at "Blizzard Entertainment | P.O. Box 18979 | Irvine, CA 92623 | United States" (with | meaning go to the next line). I hope this helped.