A Simple Fix for a Duplicate Remote Static IP

Have you ever had two devices on a remote network that have the same static IP address? Let’s be honest, the answer is yes, of course it is, it happens, no biggie, no one is judging you for how it happened. Anyway, I have good news for you, there is a super easy fix.


Log into the remote networks router (assuming this isn’t the device with the duplicate IP). Once logged in issue a show ip arp command including the address of the offending IP, in our case 10.10.0.20. The router will spit the IP address and current associated MAC address back at you.

router#show ip arp 10.10.0.20
Protocol  Address          Age (min)   Hardware Addr   Type    Interface
Internet  10.10.0.20              0           aaaa.bbbb.cccc  ARPA   FastEthernet0/0.1


Now for the fix: We will create a static ARP entry for the the listed IP address and MAC address.

Router#conf t
Router#(config)#arp 10.10.0.20 aaaa.bbbb.cccc arpa

This will keep the associated IP and MAC address from hopping back and forth between the two devices’ MAC addresses. You can now remote into the device associated with the static ARP entry you just created and change the IP address to another static address. When done, don’t forget to remove the static ARP entry.

Router#(config)#ip arp 10.10.0.20 aaaa.bbbb.cccc arpa

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