Right way to configure default route in a router

The process of sending a lot of ARP requests can consume a big percentage of  a router's CPU resources. 

One Configuration that cause a router to send a lot of ARP requests is having a default-route configured that points to an ethernet interface ((config)#ip route 0.0.0.0 0.0.0.0 f0/1) instead of the next hop address ((config)#ip route 0.0.0.0 0.0.0.0 20.1.1.1).

 When configured with an exit interface, the router instead of sending ARP request for MAC address of a next-hop address, it will send ARP request for the MAC address of the destination IP address
in each packet. That result in an excessive number of ARP requests which will cause a spike of the CPU.

Before jumping into a router and start troubleshooting it, we need to know that it's the router that is causing a poor network performance. Click here to read our blog post on how to detect the root cause of a network performance issues.

A router could be the root cause of your network performance. That is a fact. But we should not ignore that applications, servers, user's client can also be the root cause of our network performance. Click here to learn how to identify the source of your network performance.

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