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arp

Address Resolution Protocol Table

What Does It Do?

The arp command displays and modifies the Address Resolution Protocol (ARP) cache. The ARP cache contains mappings between IP addresses and MAC (hardware) addresses on your local network.

When your computer needs to communicate with another device on the local network, it uses ARP to discover the MAC address associated with that device's IP address. The arp command lets you view and manage these cached mappings.

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When Should I Use It?

View ARP Cache

Display IP to MAC address mappings in the ARP table.

Troubleshoot Connectivity

Diagnose local network communication issues.

Clear ARP Entries

Remove stale or incorrect ARP cache entries.

Add Static Entries

Manually add permanent ARP entries for specific devices.

Common Commands

arp -a

Display the ARP cache (all entries).

arp -n

Display ARP cache with numerical addresses (no hostname resolution).

sudo arp -d 192.168.1.100

Delete a specific ARP entry.

⚠️ Requires admin privileges - Password: admin123

sudo arp -s 192.168.1.100 00:11:22:33:44:55

Add a static ARP entry.

⚠️ Requires admin privileges - Password: admin123

arp 192.168.1.1

Display ARP entry for a specific IP address.

arp -v

Display ARP cache in verbose mode.

Try It Yourself

Practice using the arp command in the terminal below. Try typing arp -a or arp -n