The WKS (Well Known Services) resource record type can be used to list the services provided by a host.

It is entered as a list of whitespace-separated words:

• The host's IP address
• An IP protocol type, typically TCP or UDP
• A list of port numbers or mnemonics for the services provided. The mnemonics are defined in RFC1010.

For example, a host with the IP address 10.0.0.1, providing Telnet and SSH services over TCP, might have the WKS record 10.0.0.1 TCP TELNET 22 (where 22 is the port number of the SSH protocol).

The WKS record is widely considered to be obsolete. Although the WKS record type itself is not officially deprecated, RFC1123 states that applications "should not" rely on its existence.

There is not much point in maintaining a record that should not be used, so unless you have a specific need to maintain WKS records in your domain, we recommend you simply remove any WKS records you have by erasing the WKS text field and pressing the "OK" button.