WKS (well-known services) resource record
WKS records
describe the well-known services
supported by a particular protocol at a specified address.
The list of services and
port numbers comes from the list of services
specified in /etc/services.
There should be only one WKS record per protocol per address.
Because the WKS record is not widely used throughout the Internet, applications should not rely on the existence of this record to determine the presence or absence of a service. Instead, the application should simply attempt to use the service.
Here is an example of a WKS record:
{name} {ttl} addr-class WKS address protocol list of services IN WKS 132.147.118.1 UDP echo tftp time IN WKS 132.147.118.1 TCP (telnet discard sunrpc sftp uucp-path systat netstat qotd nntp link chargen ftp auth whois mtp pop rje finger smtp supdup hostnames domain name server)