.NODE

Viewing OSPF Status with Domain Names

Problem

You would prefer to view proper domain names rather than see the raw IP addresses in the output of your OSPF show commands.

Solution

You can configure OSPF to resolve IP addresses into router names with the following global configuration command:

Router3#configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Router3(config)#ip ospf name-lookup 
Router3(config)#end
Router3#

 

Discussion

When you configure OSPF name-lookup, the router will use its locally configured host table, if it has one, or DNS to resolve the names. If both are present, the router will check the local host table first. You can enable DNS on a router with the ip domain-lookup and ip name-server commands, as we discussed in Chapter 2.

Enabling name resolution can be useful when displaying information like OSPF neighbor tables. For example, if we look at the neighbor table without name-lookup enabled, we see IP addresses:

Router3#show ip ospf neighbor 

Neighbor ID Pri State Dead Time Address Interface
172.20.220.1 1 FULL/DR 00:00:34 172.20.10.2 Ethernet0
172.25.25.1 1 FULL/ - 00:00:31 172.20.1.1 Serial0.1
Router3#

But with name lookup, the router replaces the router IDs with names:

Router3#show ip ospf neighbor 

Neighbor ID Pri State Dead Time Address Interface
Router6 1 FULL/DR 00:00:37 172.20.10.2 Ethernet0
Router1 1 FULL/ - 00:00:36 172.20.1.1 Serial0.1
Router3#

The output will show an IP address rather than a name if the router can't resolve the address into a name, either because it can't reach the name server or because the name server doesn't include this address.

See Also

Recipe 8.8

Router Configuration and File Management

Router Management

User Access and Privilege Levels

TACACS+

IP Routing

RIP

EIGRP

OSPF

BGP

Frame Relay

Handling Queuing and Congestion

Tunnels and VPNs

Dial Backup

NTP and Time

DLSw

Router Interfaces and Media

Simple Network Management Protocol

Logging

Access-Lists

DHCP

NAT

First Hop Redundancy Protocols

IP Multicast

IP Mobility

IPv6

MPLS

Security

Appendix 1. External Software Packages

Appendix 2. IP Precedence, TOS, and DSCP Classifications

Index

show all menu





Cisco IOS Cookbook
Cisco IOS Cookbook (Cookbooks (OReilly))
ISBN: 0596527225
EAN: 2147483647
Year: 2004
Pages: 505
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