Can't find any servers!

[Stigmata]

Well, okay, that's not completely true. When I pull up the server browser on Steam, I get only 1-3 results. I don't have any filters on at all, and I can still play CSS or HL2DM or what have you.

I'm assuming the problem is somehow related to the Windows XP Service Pack 2, and the security center firewall, but I checked that, and both HL2 and Steam are unblocked, and the "scope" is set to allow access with any computer. Other than that, I have no idea what the problem could be.

Steam worked fine before I got SP2

 

[Beerdude26]

Hmmm... Have you tried just taking the firewall off? So you don't have any protection at all (and nothing to stop the signal). Then try it. If it works, it's probably the firewall. Just take the XP firewall off and install a free firewall (ZoneAlarm is pretty good). If it doesn't work, it's probably a router or your ISP blocking some ports. Although that's doubtful.

 

[Stigmata]

Well, I read up on a thread similar to this in the Hardware/Software forum, and I was pointed to some solution thing on Steam support. And it turns out that firewalls like ZoneAlarm can cause problems with steam, as can router firewalls, uPnP, and so on.

Anyway, long story short, it turned out it was my router firewall that was blocking a lot of ports. As far as I can tell, it blocked port 27015, which is basically the only port HL ever uses I think. And I happened to have forgotten the password to access my router settings, so I had to spend 45 minutes reinstalling the software and reconfiguring the router. But it's fixed now

So anyone with the same problem as me, make sure you don't have a router firewall on.