ARP

• uses ethernet frames
• and WiFi
• Bluetooth?

ARP tables

• connecting L3 and network-layer-2
• IP to mac-address

Protocol

1. Broadcast to ff:ff:ff:ff:ff:ff (e.g. “Hey, wanna send hello to 10.10.10.126”)
2. Wait for reply with MAC (router or direct host)
3. Send Ethernet frame

Attacks

• ARP cache poisoning (MAC $$\longrightarrow$$ MAC*)