Linux Debian Networkd restart kills Tailscale routing

14th September 2026

Uncategorised

Systemd-networkd deletes unmanaged custom IP routing policy rules on startup or restart because its default settings clean up “foreign” configurations. [1, 2]

Logs Show:
Sep 13 06:49:23 MySvrName tailscaled[103604]: router: somebody (likely systemd-networkd) deleted ip rules; restoring Tailscale’s
….
Sep 13 06:49:24 MySvrName tailscaled[103604]: Rebind; defIf=”eth0″, ips=[some ips NOT including tailscale]

Disable Foreign Rule Management Globally (Quickest Fix)
nano /etc/systemd/networkd.conf Under the [Network] section, add or uncomment the following lines
[Network]
ManageForeignRoutes=no
ManageForeignRoutingPolicyRules=no
ManageForeignNextHops=no

This WILL require a network service restart to apply. Maybe do this in a scheduled job in the wee hours of the morning
sudo systemctl restart systemd-networkd