DNS resolution probs after update

[YVRdarb]

New to Linux and struggling with resolving this.

After doing an update on Ubuntu 18.04.3 LTS it seems that I have lost outgoing DNS resolution.

If it helps, my netplan directory is empty, from what I have read I think that there should be a yaml file or more in it?

Thanks

[ubfan1]

There are lots of ways to handle DNS. The default in 18.04 is to use sytemd-resolved, and let your router set up DNS. Is /etc/resolv.conf a link to /run/systemd/resolve/stub-resolv.conf ? If so, what are its contents? If the nameserver is 127.0.0.53, you are using systemd-resolve. Any other nameserver and you have skipped systemd-resolve (which should work for DNS too). Can you ping the 8.8.8.8 nameserver directly? If not, then it's a network problem, not DNS. If using systemd-resolve, I recommend installing the libnss-resolve package to fix some problems with certain large outputs.

[YVRdarb]

Been busy, a slow response, but:

> Is /etc/resolv.conf a link to /run/systemd/resolve/stub-resolv.conf ? If so, what are its contents? If the nameserver is 127.0.0.53
> , you are using systemd-resolve. Any other nameserver and you have skipped systemd-resolve (which should work for DNS too).

resolve.conf is a file with nothing in it except generated by network manager.

/resolve/ doesn't exist.

> Can you ping the 8.8.8.8 nameserver directly? If not, then it's a network problem, not DNS.

Yes, can ping IP addresses.

[ubfan1]

Does ps auxww |grep [r]esolv show the /lib/systemd/systemd-resolved daemon is running? In a standard install, it should be what's managing the /etc/resolv.conf file,link to the a bove file with only 3 lines which are not comments: nameserver 127.0.0.53, options edns0, and search whateverrouteruses.net
The yaml is prety simple too:
$ cat /etc/netplan/01-network-manager-all.yaml
# Let NetworkManager manage all devices on this system
network:
version: 2
renderer: NetworkManager
The missing piece of a standard install is the libnss-resolve package, which should alter the hosts line in the /etc/nsswitch.conf file to :
hosts: files mdns4_minimal [NOTFOUND=return] resolve [!UNAVAIL=return] dns myhostname
Ensure that the systemd-resolved daemon runs at bootup -- that should fix most of the problems. the libnss-resolve issue is more esoteric- intermittent, some big outputs failing to resolve.
Upgrading from a previous release probably reuses what was previously in place, with greater or lesser success.

[YVRdarb]

ps auxww |grep [r]esolv returns nothing

probably just going to reinstall os from scratch.