This program records the Ethernet address of every device it has ever seen and the IP address that it assigned to it.

4.2.I think you're running into what I believe is a serious mis-feature of the isc-dhcp server. The ip neighbour command can only retrieve MAC addresses of computers in our local network. The second IP address is of a host in our LAN that we’ve previously pinged. The first IP is the gateway node and we can verify this by running ip route: $ ip routeĭefault via 172.16.187.2 dev ens160 proto static metric 100 That’s where the ip neighbour command comes in. Now, we run the ip neighbour command to see the corresponding MAC address for the IP we’ve just pinged: $ ping -c 1 172.16.187.129 We need a way to view the ARP cache so that we can see the MAC address.

Although the arp command still works, we’ll use the ip neighbour command in this tutorial. As a result, they use this cache to temporarily store the IP and MAC addresses of the hosts they communicate with.Īlso, it’s important to note that the arp tool is part of the net-tools package which is outdated.

All devices have an ARP cache or ARP table. Additionally, it contains a field for the target’s MAC address which, at that point, remains unknown. The ARP request includes the sender’s IP, the sender’s MAC address and the target’s IP address. The sender needs to transmit an ARP broadcast which all hosts in the LAN will receive. In most cases, the sender doesn’t know what the destination MAC address is. For the sender to know which computer to forward this packet to, it needs to have the destination IP and the destination MAC address. When a computer wants to communicate with another computer in the network, it packages the request into an IP datagram or IP packet.

For example, when a computer joins a network it has a unique IP address so that it can communicate with other hosts in the network.

How to get the mac address on linux