O'Reilly logo

31 Days Before Your CCENT Certification by Scott Bennett

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Day 17: DNS Operation

The following steps occur when a host wants to resolve a DNS name such as mail.cisco.com:

1. The host uses a resolver to query a DNS server inside its domain for the IP address of mail.cisco.com. This DNS server is preconfigured for the host.

2. The DNS server receives the request and checks its local records. If the DNS server cannot resolve the domain name, it forwards the request to another preconfigured DNS server. The local DNS server may query a root DNS server to discover the location of top-level .com domain name servers.

3. The top-level DNS server, after it is queried, responds with the location of the cisco.com DNS server for the requested domain.

4. The local DNS server queries the cisco.com DNS server for the ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required