Some mornings when my Ubuntu 18.04 wakes from hibernate, it takes around 30 minutes before I can do any DNS lookups.
I already disabled automatic DNS and added Google's DNS servers instead:
But nevertheless, I can ping
18.104.22.168 but not
Usually after much fruitless enabling/disabling Wifi, and connect and disconnecting Wifi networks, it suddenly springs into action and all is well for the rest of the day.
But here's the mystery: if Ubuntu is using
22.214.171.124 as its DNS lookup, how can it be the case that I can ping the IP but not the URL?
Here's the output of
➜ dig @126.96.36.199 www.google.com ; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> @188.8.131.52 www.google.com ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39427 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;www.google.com. IN A ;; ANSWER SECTION: www.google.com. 297 IN A 184.108.40.206 ;; Query time: 21 msec ;; SERVER: 220.127.116.11#53(18.104.22.168) ;; WHEN: Thu Aug 20 19:52:43 BST 2020 ;; MSG SIZE rcvd: 59
sudo tcpdump -ni lo port 53
This command showed nothing until about 20 minutes after booting up, at which point it exploded into life with things like:
netstat -acpn | grep ":53"
This is the output of
netstat when DNS lookup isn't working.
And with DNS working, later in the day: