To control the interface-specific handling of IP address resolution into 48-bit Ethernet, FDDI, and Token Ring hardware addresses, use the arp interface configuration command. To disable an encapsulation type, use the no form of thiscommand.
arp {arp a | probe | snap }
no arp {arpa | probe | snap }
arpa Standard Ethernet-style ARP (RFC 826).
probe HP Probe protocol for IEEE-802.3 networks.
snap ARP packets conforming to RFC 1042.
Standard Ethernet-style ARP
Interface configuration
| Release | Modification | 10.0 | This command was introduced. |
|---|
Unlike most commands that take multiple arguments, arguments to the arp command are not mutually exclusive. Each command enables or disables a specific type of ARP. For example, if you enter the arp arpa command followed by thearp probe command, the Cisco IOS software would send three (two for probe and one for arpa ) packets each time it needed to discover a Media Access Control (MAC) address.
The arp probe command allows the software to use the Probe protocol (in addition to ARP) whenever it attempts to resolve an IEEE-802.3 or Ethernet local data link address. The subset of Probe that performs address resolution is called Virtual Address Request and Reply. Using Probe, the software can communicate transparently with Hewlett-Packard IEEE-802.3 hosts that use this type of data encapsulation.
Cisco's support for HP Probe proxy support changed as of Software Release 8.3(2) and subsequent software releases. The no arp probe command is now the default. All interfaces that will use Probe must now be explicitly configured for arp probe .
The show interfaces EXEC command displays the type of ARP being used on a particular interface. To remove all nonstatic entries from the ARP cache, use the clear arp-cache privileged EXEC command.
The following example enables probe services:
interface ethernet 0 arp probe
| Command | Description |
|---|---|
| clear arp-cache | Deletes all dynamic entries from the ARP cache. |
| show interfaces | Displays statistics for all interfaces configured on the router or access server. |
Printed for apswan@ctr.ap.nic.in on Wed Mar 5 22:32:57 PST 2003
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