How to disable DNS lookup in Cisco?

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Disabling DNS Lookup

When working on Cisco Routers and switches, one gives an error command which takes it to a long queue of DNS lookup.

Not only is critical time wasted, but it also becomes an irritant especially for newbies or ones who have started recently working on cisco commands.

In fact “Cntrl+Shift+6” is also useless here.

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The router can be configured to use DNS lookups if one wishes to use the ping or traceroute commands with a hostname rather than an IP address.

List of Commands

Use these commands to do so:

Command	Description
ip domain lookup	Enable DNS-based host name-to-address translation. This command is enabled by default.
ip name-server	Specifies the address of one or more name servers
ip domain list	Defines a list of domains, each to be tries in turn. Note: If there is no domain list, the domain name that you specified with the ip domain-name global configuration command is used. If there is a domain list, the default domain name is used.
ip domain name	Defines a default domain name that the Cisco IOS software use to complete unqualified host names (names without a dotted-decimal domain name). Do not include the initial period that separates an unqualified name from the domain name.
ip ospf name-lookup	Configures Open Shortest First Path to look up DNS names for use in all OSPF show EXEC command displays. This feature makes it easier to identify a router because the router is displayed by name rather than by its router ID or neighbor ID.

But if one doesn’t want to wait forever when console becomes active again all you have to do is disable DNS lookup on the box.
By default, DNS lookup is enabled on the Cisco platform which causes delays in traceroutes and in a few other cases. You can simply disable it using the command :

R7(config)# no ip domain-lookup

I hope this article would have helped you in disable DNS lookup. More articles on DNS –

Configure DDNS in a Cisco Router

DNS Interview Questions

DNS vs MDNS

ABOUT THE AUTHOR

Rashmi Bhardwaj

Founder of AAR TECHNOSOLUTIONS, Rashmi is an evangelist for IT and technology. With more than 12 years in the IT ecosystem, she has been supporting multi domain functions across IT & consultancy services, in addition to Technical content making.

You can learn more about her on her linkedin profile – Rashmi Bhardwaj