Map hostnames to IP addresses

It is possible to define static hostname-to-address mappings on a Cisco device for the purpose of name resolution. This is usually done in environments without a DNS server.

The mappings can be defined using the global configuration command ip host HOSTNAME IP_ADDRESS:

Floor1(config)#ip host HQ_SERVER

In the output above we’ve defined the IP address of for the hostname HQ_SERVER. To display the hostname-to-address mappings, the show hosts command is used:

Floor1#show hosts
Default Domain is not set
Name/address lookup uses domain service
Name servers are

Codes: UN - unknown, EX - expired, OK - OK, ?? - revalidate
temp - temporary, perm - permanent
NA - Not Applicable None - Not defined

Host Port Flags Age Type Address(es)
HQ_SERVER None (perm, OK) 0 IP

We can ping the server using its hostname to verify that the hostnames are being resolved:

Floor1#ping HQ_SERVER

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:
Success rate is 100 percent (5/5), round-trip min/avg/max = 0/0/1 ms

You can see that HQ_SERVER responded to the ping request, which means that the name resolution was successful.

The drawback of this method of name resolution is that we need to create static hostname-to-address mappings on each device in order to be able to resolve hostnames. If possible, use DNS instead.