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Default route missing on Linux

Inspect route table, interface addresses, NetworkManager state, and resolver state before restarting networking.

Safest first command

ip route

Before you run this

Expected output: Route table output, ideally including a `default via ...` line for outbound traffic.

When not to use it: Do not restart networking on remote systems before confirming console access or another management path.

Expected output example

default via 192.0.2.1 dev eth0 proto dhcp src 192.0.2.44 metric 100

How to read the result

If no default route appears, the host may reach local networks but not the internet. If a default exists, check interface state and DNS separately.

What to check next

No default route

Means: Outbound traffic has no gateway.

Next step: Inspect interface state and NetworkManager.

Show Linux Route Table

Interface has no address

Means: DHCP or static addressing may be broken.

Next step: Read interface addresses.

Show Interface Addresses

Route exists but names do not resolve

Means: This may be DNS, not routing.

Next step: Read resolver state.

Read systemd-resolved Status

Default route decision tree

Read routes first, then addresses, manager state, and DNS. Avoid remote network restarts until you know whether they can cut off access.

  1. ip route
  2. ip addr
  3. nmcli device status
  4. resolvectl status

Bad fixes to avoid

Do not flush routes or restart networking blindly on a remote host. Do not edit resolver config when the actual issue is a missing gateway.

Common causes

  • DHCP did not install a gateway
  • Interface down
  • Wrong NetworkManager profile
  • VPN or policy route override
  • DNS confused with routing

What not to change yet

  • Do not restart networking without console access.
  • Do not add a default route before checking interface and gateway.
  • Do not treat DNS failure as route failure.

Stop and escalate if

  • The next step could interrupt users, remove data, or lock out access.
  • The output includes secrets, customer data, or private infrastructure details.
  • You cannot explain the blast radius of the repair command.

supporting commands

Command path

Guides and drills