Address Resolution Protocol
- ARP Lives in the ,Data Link Layer and **Network Link Layer
- Arp Sends out message "Who has mac address for x.y.z.a and if you know about it, send it back to me"
- Allow us to get a mac address of another devices on the network.
- Devices on the network will maintain an ARP cahce
- list of ip address to mac address association
- Arp age out cache every 90s, so arp will have to re-resolve ip to mac address every
- Switched do not need ARP tables
- You can't ARP address that is not on your local network.
show ip route # show avaliable routes on default gw.