Analyzing connectivity problems with ARP
ARP is used by IP to resolve the destination MAC address out of the IP address of the device that we wish to communicate with. When we send packets to a destination, the first packet is the ARP request to find the MAC address of the destination. We get it from the destination and then send the other packets destined to it.
ARP operation is only local, that means the ARP request, which is a broadcast, will be sent only on the LAN. In case you send a packet to a device on your IP network (with the same IP network and mask), ARP will try to find its address. When you send a packet to someone out of your network, ARP will be sent to find out the default gateway MAC address.
We will use three methods ...