Arp
Displays and modifies entries in the Address Resolution Protocol (ARP) cache, which contains one or more tables that are used to store IP addresses and their resolved Ethernet or Token Ring physical addresses. There is a separate table for each Ethernet or Token Ring network adapter installed on your computer. Used without parameters, arp displays help.
Syntax
arp [-a [InetAddr] [-N IfaceAddr]] [-g [InetAddr] [-N IfaceAddr]] [-d InetAddr [IfaceAddr]] [-s InetAddr EtherAddr [IfaceAddr]]
Parameters
-a [InetAddr] [-N IfaceAddr] : Displays current ARP cache tables for all interfaces. To display the ARP cache entry for a specific IP address, use arp -a with the InetAddr parameter, where InetAddr is an IP address. To display the ARP cache table for a specific interface, use the -N IfaceAddr parameter where IfaceAddr is the IP address assigned to the interface. The -Nparameter is case-sensitive.
-g [InetAddr] [-N IfaceAddr] : Identical to -a.
-d InetAddr [IfaceAddr] : Deletes an entry with a specific IP address, where InetAddr is the IP address. To delete an entry in a table for a specific interface, use the IfaceAddr parameter where IfaceAddr is the IP address assigned to the interface. To delete all entries, use the asterisk (*) wildcard character in place of InetAddr.
-s InetAddr EtherAddr [IfaceAddr] : Adds a static entry to the ARP cache that resolves the IP address InetAddr to the physical address EtherAddr. To add a static ARP cache entry to the table for a specific interface, use the IfaceAddr parameter whereIfaceAddr is an IP address assigned to the interface.
/? : Displays help at the command prompt.
Remarks
| • | The IP addresses for InetAddr and IfaceAddr are expressed in dotted decimal notation. |
| • | The physical address for EtherAddr consists of six bytes expressed in hexadecimal notation and separated by hyphens (for example, 00-AA-00-4F-2A-9C). |
| • | Entries added with the -s parameter are static and do not time out of the ARP cache. The entries are removed if the TCP/IP protocol is stopped and started. To create permanent static ARP cache entries, place the appropriate arp commands in a batch file and use Scheduled Tasks to run the batch file at startup. |
| • | This command is available only if the Internet Protocol (TCP/IP) protocol is installed as a component in the properties of a network adapter in Network Connections |
Examples
To display the ARP cache tables for all interfaces, type:
arp -a
To display the ARP cache table for the interface that is assigned the IP address 10.0.0.99, type:
arp -a -N 10.0.0.99
To add a static ARP cache entry that resolves the IP address 10.0.0.80 to the physical address 00-AA-00-4F-2A-9C, type:
arp -s 10.0.0.80 00-AA-00-4F-2A-9C
