Tuesday, February 3, 2009

DNS

DNS timeouts have been pretty bad lately; decided to take action and make resolve.conf actually be usable. Of course, it gets overwritten every time DHCP is used to configure an interface, so the name servers have to be added to dhclient.conf .

There are quite a lot of reliable servers to choose from:

OpenDNS
TechFAQ public dns server list
dnsserverlist.org
dnsserverlist.org organized by round trip time

The last two are particularly useful: dnsserverlist.org recommends three DNS servers based on your current IP, and provides an option for sorting their list by round-trip-time.

"Permanent" DNS servers can be added by editing /etc/dhcp3/dhclient.conf and adding 'prepend domain-name-servers' lines:

prepend domain-name-servers 216.224.112.14;
prepend domain-name-servers 67.198.198.213;
prepend domain-name-servers 69.111.95.106 ;
prepend domain-name-servers 208.67.222.222;
prepend domain-name-servers 208.67.220.220;
prepend domain-name-servers 4.2.2.1;
prepend domain-name-servers 4.2.2.2;
prepend domain-name-servers 151.197.0.38;
prepend domain-name-servers 151.202.0.84;
prepend domain-name-servers 151.203.0.84;

Remember to list these in reverse-order: the last server prepended will be the first line in resolv.conf.

The ultimate solution, of course, is to set up a local caching DNS server.

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