For the past two weeks I have been puzzled by this.

A few hosts simply wont answer http requests. These hosts include

*.mail.live.com -- used by Hotmail (http://www.hotmail.com)

assets.espn.go.com -- used by Soccernet (http://www.soccernet.com)

static.ak.fbcdn.net -- used by Facebook (http://www.facebook.com)

There are probably more, but there are the ones most people have complained about.

All these sites are resolved fine through both OpenDNS and CATs own DNS servers, but no data is received.

I have had contact to CAT on several occasions and they claim everything is working fine. When I connect to these servers through my proxy everything is working fine.

I had a similar incident with Google a while back.

Any suggestions on what to do here?

I resolved an issue sim to this with a forum I use all the time.  I found it worked with proxy twice as fast as normal and sometimes normal connections timed out.  I found my MTU had got bumped up to 1500 and lowered it back to the 1492 and all my connection started working better.  Just a shot in the dark here.

Just a shot in the dark here.

Those are most welcome, since I find myself really in the dark here.

Another thing I noticed is that all torrent trackers reply with: Access Denied (4xx)

Not that I care, it actually free up our connection when people cannot run P2P.

For the past two weeks I have been puzzled by this.

A few hosts simply wont answer http requests. These hosts include

*.mail.live.com -- used by Hotmail (http://www.hotmail.com)

assets.espn.go.com -- used by Soccernet (http://www.soccernet.com)

static.ak.fbcdn.net -- used by Facebook (http://www.facebook.com)

I had exactly the same issue with facebook and other sites for 3 days until yesterday - I fixed it by removing the OPENDNS settings and replacing them with the first CAT DNS ip's I found in google:

202.129.27.135

61.19.245.246

You mention you have tried CAT DNS already - but this fixed my issues 100% so it might be worth another shot.