Cisco 1700 ARP table corruption

[marsss]

Anyone know what can make my ARP table corrupted in a Cisco 1700.

I have a steady 3 mbps full duplex going trough this router and he is main gateway of my network. When his table get corrupted it mess up all my network.

 

[JOAMON]

Is the default route through an ethernet interface?

 

[jneiberger]

How do you know it is being corrupted? What exactly do you mean by "corrupted"?

 

[marsss]

By corrupted I mean :

ARP table show IP address correctly
But mac address show as "Incomplete" instead have the mac address

And LAN interface (which receive all gateway request) is a FastEthernet interface. Ethernet one is on Internet side

 

[JOAMON]

If your default route looks like the following:

ip route 0.0.0.0 0.0.0.0 ethernet1

Try changing it to the following:

ip route 0.0.0.0 0.0.0.0 XXX.XXX.XXX.XXX

X=ip address of next hop router

Clear the arp cache and see if that helps.

 

[jneiberger]

Incomplete simply means that the router is not able to resolve the MAC address. In other words, the router is sending an ARP request to the device but it is not receiving an ARP reply. This could be a problem on the switch that the router is connected to or that the devices are connected to. Regardless, if it is happening often and it happens to numerous IP address at the same time then you definitely need to do some troubleshooting outside of the router.