DNS technical information

A valid "A" record within the ox.ac.uk domain must be present for all hardware assigned and using IP addresses within the ranges assigned to Oxford University.

This includes printers and network hardware, especially if they are sending or receiving packets via the University backbone (from time to time packets may leak onto the backbone even if you do not expect them to). Lack of DNS entry may result in access being denied to certain services; moreover it makes it easier for IT Services and external sites to identify machines in the event of problems. Obviously machines on private networks within departments (using "private" IP address ranges such as 10.0.0.0/24) need not be registered in the DNS, but any gateway/firewall connecting them to the University network must be registered.

Library public machines may be placed within the library-public.ox.ac.uk subdomain in an effort to prevent their being used to access central email services.

Please note that while there are around 100 hosts registered in this domain, it is not believed that central email services still adhere to NAG's policy.

Normally most hosts on your network will lie within a single subdomain, although some departments may have multiple subdomain names to reflect internal organisation.

Some units may wish for certain servers to be accessible via a different subnet name, for instance the long-format name as used on email addresses (www.longunitname.ox.ac.uk). Hostmaster may choose to allow these as aliases for primary public WWW and FTP servers, but other machines will remain within the standard unit name.

To avoid your NAT gateway being mistaken for a standard host, IT Services strongly recommend that you give it a distinctive name in the DNS, for example student-nat.unit.ox.ac.uk.

The DNS resolvers may respond to queries with information as directed by OxCERT on security grounds.

The University is running short of unallocated IPv4 subnets. We have to ensure that we are able to allocate subnets to new departments over the next decade and longer that it will take before it will be viable to run IPv6 only. This means that we are unable to allocate new subnets greater than /24 in size and that existing Units will be expected to stay within their existing allocation (e.g. by the use of NAT/PAT).

A DNS entry must not contain characters other than alphanumeric characters, dashes, and dots to separate the various components. DNS is case-insensitive.