ARP.exe – Windows CMD Command
ARP – Address Resolution Protocol
Display and modify the IP-to-Physical address translation tables used by address resolution protocol.
View the contents of the local ARP cache table
ARP -a [ip_addr] [-N if_addr]
Add a static Arp entry for frequent accessed hosts
ARP -s ip_addr eth_addr [if_addr]
Delete an entry
ARP -d ip_addr [if_addr]
-a Display current ARP entries.
Can include more than one network interface.
If ip_addr is specified, the IP and Physical
addresses for only the specified computer are displayed.
-g Same as -a.
-N if_addr Display the ARP entries for the network interface specified
-d ip_addr Delete the host specified by ip_addr.
-d * will delete all hosts.
-s Add the host and associates the Internet address ip_addr
with the Physical address eth_addr. The Physical address is
given as 6 hexadecimal bytes separated by hyphens. The entry
eth_addr Specifies a physical address.
if_addr If present, this specifies the Internet address of the
interface whose address translation table should be modified.
If not present, the first applicable interface will be used.
If two hosts on the same subnet cannot ping each other successfully, try running ARP -a to list the addresses on each computer to see if they have the correct MAC addresses.
A host’s MAC address can be checked using IPCONFIG. If another host with a duplicate IP address exists on the network, the ARP cache might have had the MAC address for the other computer placed in it. ARP -d is used to delete an entry that is incorrect.
Display the ARP cache tables for all interfaces:
C:\> arp -a
Display the ARP cache table for the interface on IP address 10.1.4.99:
C:\> arp -a -N 10.1.4.99
Add a static ARP cache entry on IP addr 10.1.4.77 to the physical address 00-AA-21-4A-2F-9A:
C:\> arp -s 10.1.4.77 00-AA-21-4A-2F-9A