Troubleshooting

DNS Resolver

Syntax: [no] ip dns domain-name < domain-name-suffix>

This optional DNS command configures the domain suffix that is automatically appended to the host name entered with a DNS-compatible command. When the domain suffix and the IP address for a DNS server that can access that domain are both configured on the switch, you can execute a DNS-compatible command using only the host name of the desired target. (For an example, refer to Figure C-25 on page C-80.) In either of the following two instances, you must manually provide the domain identification by using a fully qualified DNS name with a DNS-compatible command:

If the DNS server IP address is configured on the switch, but the domain suffix is not configured (null)

The domain suffix configured on the switch is not the domain in which the target host exists

The switch supports one domain suffix entry and three DNS server IP address entries. (Refer to the preceding command description.)

The no form of the command replaces the configured domain suffix with the null setting. (Default: null)

Example Using DNS Names with Ping and Traceroute

In the network illustrated in Figure C-27, the switch at 10.28.192.1 is configured to use DNS names for DNS-compatible commands in the pubs.outdoors.com domain. The DNS server has been configured to assign the host name docservr to the IP address used by the document server (10.28.229.219).

 

Switch “A” Configured

 

 

 

 

 

 

Document

 

 

with DNS Resolver

 

 

 

Router “B”

 

 

Server

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10.28.192.1

 

 

 

 

10.28.192.2

 

 

docservr

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(10.28.229.219)

 

 

 

 

 

 

10.28.229.1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DNS Server for pubs.outdoors.com

 

 

 

 

 

 

 

 

10.28.229.10

 

 

 

 

 

 

 

 

Host Name for IP address

 

 

 

 

Domain: pubs.outdoors.com

 

10.28.229.219 = “docservr”

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure C-27. Example Network Domain

C-83