I see this behaviour too, quite often on multiple machines, always seemingly happening when the machine is under high load. When it happens, systemd-networkd typically logs something like:
systemd-networkd[3512]: enp193s0f0np0: Could not set route: Connection timed out systemd-networkd[3512]: enp193s0f0np0: Failed In my eyes there are two or three problems here: 1. networkd is deleting and re-adding a route when it probably doesn't need to (I guess when it receives an ICMPv6 router advertisement); the route hasn't changed and an identical one already exists in the routing table 2. The error is handled poorly; perhaps it could retry 3. After the error, the default route stays missing _permanently_ (until systemd-networkd is prodded with e.g. "netplan apply"); at the very least it ought to try to re-add the route next time it sees an RA packet ** Bug watch added: github.com/systemd/systemd/issues #25441 https://github.com/systemd/systemd/issues/25441 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2053288 Title: systemd-networkd IPv6 default routes dropped under load, don't recover To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/2053288/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
