NTP client setup

We're using chrony as the NTP client in this setup. As an NTP server we'll use the default gateway

sudo apt update
sudo apt install chrony

Remove ubuntu pools, add GW as server

/etc/chrony/chrony.conf

#...
#pool ntp.ubuntu.com        iburst maxsources 4
#pool 0.ubuntu.pool.ntp.org iburst maxsources 1
#pool 1.ubuntu.pool.ntp.org iburst maxsources 1
#pool 2.ubuntu.pool.ntp.org iburst maxsources 2
server 192.168.120.1 iburst
#...

Restart service

sudo systemctl restart chrony
chronyc sources