My ability to update stopped recently, with all calls to *ubuntu.com and ubuntuforums.com failing completely. Things just time out, but other sites work just fine.

It's happening upstream of my router; traceroute from my router fails to connect. It's not on my computer either; when connected on wifi, my Android phone fails to connect also, but when I get off wifi my phone gets to ubuntu.com without problems.

I can visit ubuntu.com in a browser only if I go through an anonymous proxy.

The problem isn't DNS, either, as it resolves an IP address, but I tried a few different DNS servers just in case.

I've tried updating my repositories in package manager, but they all also fail.

What happened? Is it possibly my ISP blocking all traffic to ubuntu.com and the mirror domains? Is ubuntu mad at my IP address or range?

I am running Linux Mint 13, Kernel 3.2.0-26-generic-pae.