Computer and Software Support


ARP

This page is from Microsoft

Updated: January 21, 2005

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] [-NIfaceAddr]] [-g [InetAddr] [-NIfaceAddr]] [-dInetAddr [IfaceAddr]] [-sInetAddr EtherAddr [IfaceAddr]]
Parameters
-a[ InetAddr] [ -NIfaceAddr]
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. If InetAddr is not specified, the first applicable interface is used. To display the ARP cache table for a specific interface, use the -NIfaceAddr parameter in conjunction with the -a parameter where IfaceAddr is the IP address assigned to the interface. The -N parameter is case-sensitive.
-g[ InetAddr] [ -NIfaceAddr]
Identical to -a.
-dInetAddr[ 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.
-sInetAddr 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 where IfaceAddr 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.
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

Formatting legend

 
Format Meaning
Italic Information that the user must supply
Bold Elements that the user must type exactly as shown
Ellipsis (...) Parameter that can be repeated several times in a command line
Between brackets ([]) Optional items
Between braces ({}); choices separated by pipe (|). Example: {even|odd} Set of choices from which the user must choose only one
Courier font Code or program output

Some of these terms may be the same or similar to DOS commands. For information on DOS Commands, click here