Check that your /etc/netplan/ file includes IPv4 DNS in addition to IPv6

sudo apt install traceroute net-tools

Set ENABLED=1 to ENABLED=0 in /etc/default/motd-news to disable MOTD adverts.

sudo vi /etc/default/motd-news

Comment out the lines in /etc/update-motd.d/10-help-text to hid the documentation links.

sudo vi /etc/update-motd.d/10-help-text

Add the following to /etc/netplan/00-…. Remember you must specify an IPv6 gateway. Remember, this must go just after the interface address.

dhcp4: false
dhcp6: false
accept-ra: false