Recursive DNS servers

The struck-through names in the tables below are old names that are being deprecated as part of our renaming and renumbering project.

We have a resolver test page that you can use to compare DNS responses from our resolvers with responses from several commercial public DNS servers.

Default resolvers

These are the usual recommended DNS servers; for example, you will be using these servers if you connect to Wi-Fi / eduroam.

They implement DNS RPZ blocks and encrypted queries.

server names IPv4 IPv6
rec0.dns.cam.ac.uk
recdns0.csx.cam.ac.uk
131.111.8.42 2001:630:212:8::d:0
rec1.dns.cam.ac.uk
recdns1.csx.cam.ac.uk
131.111.12.20 2001:630:212:12::d:1

Pass-through resolvers

There are alternative DNS server addresses hosted on the same hardware as the default resolvers. These are available if you need un-blocked access to the DNS. They also provide encrypted queries.

If a legitimate site is blocked and this is causing problems for you, please report the error to CSIRT rather than switching to the pass-through resolvers.

server names IPv4 IPv6
raw0.dns.cam.ac.uk 131.111.9.99 2001:630:212:8::d:2
raw1.dns.cam.ac.uk 131.111.12.99 2001:630:212:12::d:3