Having a very strange problem for the last 3 days while trying to upgrade to 11.24. It reports that it can't reach diff.cpanel.net

I'm wondering if there's some sort of network problem at the planet or something that is stopping DNS lookup of this. And why would it be blocked?

I go to shell and things get really strange,

telnet diff.cpanel.net 80
ping diff.cpanel.net

Both sit there showing nothing for a ling time, then says "diff.cpanel.net: Host name lookup failure".

telnet 75.127.84.226 80
ping 75.127.84.226

Both work fast like they should (I got the IP from nwtools.com)

I can ping yahoo, google, theplanet.com, plus other big sites and it looks all of those up OK. Even ping cpanel.net works OK.

This is not a cPanel software problem as far as I can tell since I can't resolve from ssh.

Details:
Did a server reboot already. Same thing happens.
Put a OpenDNS server into resolv.conf just to test that too (standard planet NS3, NS1 etc otherwise)
The server is in the original datacenter, I think it's called D1.
Same problem with layer2.cpanel.net (which looks like it goes to the same servers)
The diff.cpanel.net server look like they are on a cluster setup, a bunch of different IPs.

Current resolv.conf
nameserver 216.185.111.10
nameserver 70.84.160.10
nameserver 67.19.0.10
nameserver 208.67.222.222

Update, I watched the server actually contact theplanet DNS server at 216.185.111.10 and it did respond with DNS info, but connections still just sit there like before. I don't know what is going on. I can ping yahoo.com and watch it do DNS and all that OK. From a home IP I can ping diff.cpanel.net with no problems so it's not that diff.cpanel.net has it's ping blocked.

And nscd is NOT running on the server, I was thinking some sort of local cache wasn't working right, but the complete reboot I did earlier should have cleared it anyway.