check if device online via ping ip when ip changes

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http://stackoverflow.com – Suppose I have the following situation. I have a Linux box sitting inside a local network, and that box will periodically ping the ip addresses of other devices on the network to make sure they are up. Also assume I know the MAC addresses of these devices, which I obtained via ARP at some point in the past. Now assume that one of the devices goes down and when it comes back up it is assigned a new ip address. How can I modify my periodic ping check to ping the new ip address? Yes I know I can check the arp table on my Linux box to get the new ip address if the record exists. But what guarantee (HowTos)