How do I check the default gateway and route used by my Linux server?
The routing table determines which interface and gateway carry traffic to a destination. Listing a default route is useful, but ip route get is more specific because it shows the route the kernel would select for the address you ask about. Neither command transmits application traffic or changes a route.
Before you start
- The real destination IP involved in the problem.
Instructions
1. Read the current routes
Inspect both address families when the server is expected to support them. A default route may use a gateway, a point-to-point interface or a provider-specific routed design; use the supplied network specification as the reference.
ip -4 route show
ip -6 route showThese commands list the IPv4 and IPv6 routing tables without modifying them.
2. Check the route to one destination
Replace the documentation address with the actual destination. Read the dev and src values as well as via, when present. A correct-looking route still needs a separate connectivity test.
ip route get 198.51.100.20Shows the selected outgoing interface and source address for this destination.
3. Account for policy routing
Multiple interfaces, VPNs or management networks may select different tables. Collect policy rules if the selected path differs from the ordinary default route.
ip rule showLists policy-routing rules in priority order.
Check the result
- The selected source and interface match the intended network.
- A subsequent test to the real service succeeds using the same destination and address family.
Troubleshooting
- Network is unreachable
- Check whether the address family has a usable address and route. Do not insert a guessed default gateway over the active SSH connection.
Official references
Use the documentation for your installed version when a flag, service name or platform feature differs.