Method by which any host or router on a LAN can dynamically learn
the MAC address of another IP host or router on the same LAN
“if this is your IP address, please reply with your MAC address.”
Each time a host or router needs to send a packet
encapsulated in an Ethernet frame, it first checks its ARP
cache for the correct IP address and matching MAC address
Hosts and routers will let
ARP cache entries time out to
clean up the table, so
occasional ARP Requests can
be seen.
Ping
Packet Internet Groper) uses the
Internet Control Message Protocol
(ICMP), sending a message called
an ICMP echo request to another IP
address.
The computer with that IP address
should reply with an ICMP echo reply.