Domain Name System

A domain name (for example, extreme.router.com) can be used in place of an IP address for certain operations such as IP pings, trace routes, and Telnet management connections to the router. A domain name is easier to remember than all of the numbers in an IP address. DNS has several components.

• DNS server: A DNS server stores the information about a DNS domain. DNS servers are a key element of DNS because they respond to queries against its database. When a DNS domain is defined on this device to recognize all hosts in that domain, this device automatically appends the appropriate domain to the host address and forwards it to the DNS server.
• DNS resolver: In a Layer 2 or Layer 3 device, the DNS resolver sends and receives queries to and from the DNS server on behalf of a client. You can create a list of domain names that can be used to resolve host names. This list can have more than one domain name. When a client performs a DNS query, all hosts in the domains in the list can be recognized and queries can be sent to any domain on the list. After you define a domain name, the device automatically appends the appropriate domain to a host and forwards it to the DNS servers for resolution.
• DNS gateway addresses: Gateway IP addresses that are assigned to the device enable clients that are attached to the device to reach DNS.