Using custom DNS may not be so great after all.

[anon]

They can break CDNs that rely on you using your provider's ones to know where you are, and work effectively.

Why using Google DNS / OpenDNS is a bad idea - APC
Centric IT » Why NOT to use Google’s DNS and similar

They will think they're on the country your custom DNSs are and serve content from there, which is a less-efficient path.

After finding those articles yesterday night, I did some small testing - ran a traceroute to www.example.com.nyud.net (which is example.com on the Coral CDN), using DNSResolvers, which are located in Canada. The final host in the chain was in that same country. I flushed my cache, switched to my ISP's servers and did the same thing: the path was shorter and ended in Brazil, a neighboring country.

[Instab]

luckily you can use more than one dns. just use a good mixture and you'll get everywhere

[anon]

luckily you can use more than one dns. just use a good mixture and you'll get everywhere

The problem here is that you're forced to use one within your country or your provider's defaults for maximum efficiency with CDNs that "hack" upon the system. Not all of them do though - YouTube will deliver videos from servers in your region even if you're using DNSs on the other side of the world.