Cara menambahkan DNS di Cisco

ping google.com
Translating "google.com"% Unrecognized host or address, or protocol not running.

ip domain-lookup

ip name-server example.com
or
ip name-server 8.8.8.8

Jika sudah di tambahkan maka kita coba tes ping kembali,

R1(config)#do ping google.com

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.217.194.139, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/16/24 ms

cek tutorial lengkap cisco disini.