Yes, the critical connection is the option to use in this case. You may also check the leases themselves in /run/systemd/netif/leases and check if the T1/T2/Lifetime are sensible, with each subsequent one higher than the prior. And if not, contact your ISP support to correct those.
** Changed in: systemd (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1776013 Title: systemd-networkd: DHCP lease lost (Ubuntu 18.04) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1776013/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs