There are times when one needs to reach a certain device on the network and cannot as multiple devices have the same IP address. This should in theory not happen but it does in networks where people can freely connect devices themselves. If the device has a static IP address which another device already has, it is nearly impossible to reach it to reconfigure it remotely as packets would end up on the wrong device. This where a static ARP entry can smooth out things forcing the router to only send packets to that single device of one’s choicesudo arp -s 192.168.0.1 e4:ea:b4:08:a8:32 -i eth1
This tells the router that “192.168.0.1” is at MAC “e4:ea:b4:08:a8:32” and will stop it broadcasting ARP requests; it just sends packets directly to that MAC.
When done simply delete it again:sudo arp -d 192.168.0.1 -i eth1
After that, the router will go back to the normal ARP behaviour of broadcasting ARP requests instead of using the fixed MAC.
If you run show arp eth1 after deletion, you should see the static entry removed.