How DNS used to resolve hostname in the CISCO router?

[Calverta]

Here I would like to know the DNS configuration which is used to resolve the host name on a large scale network.

[Theking]

Firstly, I would like to tell you that DNS map Domain name to IP address and this information is cached across the network and if this info is updated this will propagate across the DNS server and no matter what level of network is. The client side of DNS is called DNS resolver. It is responsible for initiating and sequencing the queries that lead to full translation of domain name into an IP address.

[Pabloa]

Actually DNS used several name servers to find needed information. There are some resolver function which communicate only with single name server, these are simple resolver or stub resolver and they are rely on recursive name server to perform finding information for them.

[Alejandro80]

With the help of known addresses of the root name server, a network host is configured with an initial cache and it is periodically updated by an administrator from a reliable source. To find the server authority of the top level domain, one query is fired to one of the root server.

For the second level domain, a query fired to the obtained top level domain server for the address of a DNS server authoritative. We repeat this process, until we will get the IP address of host sight, for each domain label in sequence.