Resolving DNS service

“Resolving DNS” is the type of DNS service usually referred to when an internet provider talks to their customers about their “DNS servers”. It is a different type of DNS service to “content DNS”. You can read the difference between content and resolving DNS services on our how DNS works page.

DNS is the internet service that translates internet server names to numbers, and nearly every computer on the internet needs to know how to do this to function correctly. Although you can set your virtual machine to run its own resolving DNS server, this is probably not necessary. You can tell 99% of Linux applications which DNS servers to use by editing the file /etc/resolv.conf. By default we set machines up to use our own DNS servers which are located at these IP addresses:

80.68.80.24 80.68.80.25

So your /etc/resolv.conf should look like this:

search yourdomain.co.uk nameserver 80.68.80.24 nameserver 80.68.80.25

To test your resolving DNS service you should use the dig tool to ask for a name to be looked up with your system’s default DNS service, i.e.

# normal "A" record lookup
dig www.manchester.ac.uk 
# "MX" record lookup for mail delivery
dig mx manchester.ac.uk 
# "NS" record; who's authoratitive for this domain?
dig ns bytemark.co.uk 

If dig is timing out or taking too long, you can send a DNS query directly to a particular server to check that it is working. This ignores your system’s currently configured DNS settings:

# test Bytemark's name server
dig ns bytemark.co.uk @80.68.80.24
# test Manchester University's name server
dig ns bytemark.co.uk @130.88.13.7