Cisco Cisco IOS Software Release 12.4(4)T

To define a default domain name that the Cisco IOS software uses to complete unqualified hostnames 
(names without a dotted-decimal domain name), use the ip domain name command in global 
configuration mode. To disable use of the Domain Name System (DNS), use the no form of this 
command.

ip domain name [vrf vrf-name] name

no ip domain name [vrf vrf-name] name

Enabled

Global configuration

Any IP hostname that does not contain a domain name (that is, any name without a dot) will have the dot 
and cisco.com appended to it before being added to the host table.

If the ip domain name vrf command option is specified, the domain names are only used for name 
queries in the specified VRF.

The Cisco IOS software will still accept the previous version of the command, which is 
ip domain-name.

The following example shows how to define cisco.com as the default domain name:

ip domain name cisco.com

The following example shows how to define cisco.com as the default domain name for vpn1:

ip domain name vrf vpn1 cisco.com

vrf vrf-name

(Optional) Defines a Virtual Private Network (VPN) routing and 
forwarding instance (VRF) table. The vrf-name argument specifies a 
name for the VRF table.

Default domain name used to complete unqualified hostnames. Do 
not include the initial period that separates an unqualified name from 
the domain name.

10.0

This command was introduced.

12.2

The syntax of the command changed from ip domain-name to 
ip domain name.

12.4(4)T

The vrf keyword and vrf-name argument were added.