Why Does a Linux Server Lose Its Default Route After Reboot?

A server can have working network connectivity until reboot, then lose its default route because settings were temporary, cloud-init overwrote them, or multiple network managers compete. Remote access may be lost if no console path is available.

What to check

Check persistent network configuration, interface names, DHCP leases, cloud-init logs, routing tables, and active network manager. Compare the route before and after restart and confirm the upstream gateway is reachable.

Recommended next step

Make the route persistent using the system’s supported network configuration and test through a console or maintenance window. Remove conflicting configuration sources only after identifying which service owns the interface.

How Informatix Systems can help

Informatix Systems provides Linux server and network administration services. We can review the environment, trace the problem through its dependencies, and help plan a practical resolution. Contact us with the system involved, when the issue began, and non-sensitive error details.