Internet Problems "Host is Down" For all but Safari and Ichat

I don't really know what;s going on -- this has all happened fairly recently.

I can't access much of the internet except thru Safari and Ichat.

Adium won't connect, it tells me "host is down"
Mail won't send, it also says "error 64: host is down"
My bittorrent won't work either.
I've opened my firewall thru system preferences and don't know what to do.
I'm using a 2Wire router.

Any thoughts on how to troubleshoot?

even better is turning it on and off, which has solved everything but my adium problem, which i can handle...thnx 🙂