Yesterday I had problems when using one of the TelstraClear DNS (203.96.152.4 paradise.net.nz) and decided to switch to OpenDNS.
All very nice, even created an account - but then I couldn't access Facebook to reply to some comments in my status.
I thought it could be OpenDNS and changing back to TelstraClear DNS fixed the problem. I tried again today and couldn't load Facebook.
Sometimes I see error messages when accessing some international providers - mainly ad servers for sites such as Digg or Slashdot. The space where the ad would show comes with "TCP Error".
So I am thinking that
a) TelstraClear uses a transparent proxy
b) This transparent proxy is overloaded or incorrectly configued
c) OpenDNS gives me a DNS for Facebook that is probably different from what TelstraClear usually reports - and the OpenDNS entries are to servers for which the TelstraClear proxy is having problems accessing.
So, how do we get around this? I understand the use of transparent proxy, but for some dynamic content domains they just don't work...