The name server allows your server to recognize the IP addresses of host names. You should try to always have a functioning name server added. Removing name servers from a running server is not recommended unless the name server is dead. You can have multiple name servers added and can add one of WebMaster's core name servers by adding default.
ADD - Add a nameserver
DEL - Delete a namserver
LIST - Display your namserver setup
/as help general nameserver <topic>
Once initially configured, you should not need to change this setup. However, if you know that one of your name servers is no longer responding then you should delete it.