Troubleshooting IP Routing

Troubleshooting IP routing involves identifying and resolving issues related to the routing of IP packets between networks. Here are some steps you can take to troubleshoot IP routing issues:

Verify connectivity: Check whether the devices can ping each other using their IP addresses. If the devices can ping each other, it indicates that there is basic connectivity between them.

Verify routing tables: Use the “show ip route” command to check the routing table on each router. Verify that the correct networks are present in the routing table and that they have the correct next hop address.

Verify routing protocols: Use the “show ip protocols” command to check the status of the routing protocols on the router. Verify that the correct routing protocol is running and that it is advertising the correct networks.

Check for routing loops: A routing loop occurs when a packet is forwarded between routers in an endless loop. Use the “traceroute” command to trace the path of a packet through the network and identify any loops.

Check for routing black holes: A routing black hole occurs when a packet is dropped due to a missing route in the routing table. Use the “ping” command to test the connectivity between the devices and identify any black holes.

Check for routing flapping: Routing flapping occurs when routes are continuously added and removed from the routing table due to network instability. Use the “debug ip routing” command to monitor the routing table and identify any flapping.

Check for interface errors: Interface errors can cause routing issues by preventing packets from being transmitted or received. Use the “show interface” command to check the status of the interfaces and identify any errors.

Check for firewall issues: Firewall rules can block or filter traffic, causing routing issues. Check the firewall rules on the devices and verify that they are not blocking any necessary traffic.

By following these steps, you can identify and resolve IP routing issues and ensure that your network is functioning correctly.