What is the reason for identifying the DNS name resolver in the perimeter router's config? The DNS name resolver server"s IP is indicated in the MS domain controller/Active Directory. Could someone xplain the utility of placing the DNS name server in the router's config.
It is not a requirement.
Most fo the time i have seen it being configured to test an interent link when it gets delivered mostly by connecting a laptop directly to the router. you need a devcie which need to the ip-name resolutions and hence we configure this but forget to remove.
It may also have been configured to use DNS lookups if you wish to use the ping or traceroute commands with a host name rather than an IP address