Before assuming it is a DNS problem test to see is DNS is working:
router#ping opens3.net Translating "opens3.net"...domain server (192.168.122.1) [OK] Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 138.197.226.249, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 260/269/292 ms router#
If your router/switch is able to convert a domain name to an IP address, DNS is working.
To troubleshoot DNS:
- Test general network connectivity
router#ping 1.1.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 36/46/60 ms router#
2. Test reach-ability of DNS server
router#show ip dns view DNS View default parameters: Logging is off DNS Resolver settings: Domain lookup is enabled Default domain name: Domain search list: Lookup timeout: 3 seconds Lookup retries: 2 Domain name-servers: 192.168.122.1 Resolver source interface: GigabitEthernet0/0 DNS Server settings: Forwarding of queries is enabled Forwarder timeout: 3 seconds Forwarder retries: 2 Forwarder addresses:
router#ping 192.168.122.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.122.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/13/28 ms router#
3. Check ACLs
router#show ip access-lists