[TBD]Tips to troubleshoot dns issue if ping is working

Check if DNS server is sending response

In this step, start tcpdump and perform ping to a server (for example, google.com)

root@4a1019104a23:/# ping google.com

PING google.com (216.58.196.110) 56(84) bytes of data.

64 bytes from maa03s19-in-f110.1e100.net (216.58.196.110): icmp_seq=1 ttl=54 time=17.7 ms

64 bytes from maa03s19-in-f110.1e100.net (216.58.196.110): icmp_seq=2 ttl=54 time=173 ms

root@4a1019104a23:/tmp# tcpdump -n host 10.140.50.5

tcpdump: WARNING: ns0: no IPv4 address assigned

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

listening on ns0, link-type EN10MB (Ethernet), capture size 65535 bytes

19:04:08.824833 IP 172.17.0.5.50289 > 10.140.50.5.53: 20137+ A? google.com. (28)

19:04:08.826513 IP 10.140.50.5.53 > 172.17.0.5.50289: 20137 1/0/0 A 216.58.196.110 (44)

19:04:08.845095 IP 172.17.0.5.17877 > 10.140.50.5.53: 3306+ PTR? 110.196.58.216.in-addr.arpa. (45)

19:04:08.847577 IP 10.140.50.5.53 > 172.17.0.5.17877: 3306 2/0/0 PTR maa03s19-in-f110.1e100.net., PTR maa03s19-in-f14.1e100.net. (115)