Commands Reference, Volume 1

arp Command

Purpose

Displays and modifies address resolution, including ATM (Asyncronous Transfer Mode) interfaces.

Syntax

To Display ARP Entries

arp { [ -t ifType ] HostName | -a [ n ] [ /dev/kmem ] }

To Display ARP ATM Entries

arp { -t atm HostName | -a [ n ] [ /dev/kmem ] [ pvc | svc ] }

To Delete an ARP Entry

arp [ -t ifType ] -d HostName

To Delete a PVC ARP ATM Entry

arp -t atm -d pvc vpi:vci if ifName

To Create an ARP Entry

arp [ -t ifType ] -s Type HostName AdapterAddress [ Route ] [ temp ] [ pub ]

To Create an SVC ARP ATM Entry

arp -t atm -s Type HostName AdapterAddress [ temp ]

To Create a PVC ARP ATM Entry

arp -t atm -s Type pvc vpi:vci { HostName | if ifName } [ no-llc ] [ no-arp ] [ temp ]

To Import ARP Entries from Another File

arp [ -t ifType ] -f FileName [ Type ]

Description

The arp command displays and modifies the Internet-to-adapter address translation tables used by the Address Resolution Protocol. The arp command displays the current ARP entry for the host specified by the HostName variable. The host can be specified by name or number, using Internet dotted decimal notation.

Flags

-a	Used as { [ -t ifType ] HostName \| -a [ n ] [ /dev/kmem ] } Displays all of the current ARP entries. Specify the -a /dev/kmem flag to display ARP information for kernel memory. The 'n' modifier causes hostname lookups to be suppressed. Used as { -t atm HostName \| -a [ n ] [ /dev/kmem ] [ pvc \| svc ] } The pvc specification will display only ATM PVC (Permanent Virtual Circuits) types of virtual circuits, svc specification will display only ATM SVC (Switched Virtual Circuits) types of virtual circuits. If the pvc \| svc parameter is omitted, all ATM virtual circuits will be displayed.
-d	Used as [ -t ifType ] -d HostName Deletes an entry for the host specified by the HostName variable if the user has root user authority. Used as -t atm -d pvc vpi:vci if ifName Deletes a PVC ARP entry by specifying vpi:vci rather than hostname. The vpi:vci variables specify the virtual circuit that is to be deleted. The ifname variable specifies the name of the ATM interface on which the virtual circuit is to be deleted.
-f FileName `[Type]`	Causes the file specified by the FileName variable to be read and multiple entries to be set in the ARP tables. Entries in the file should be in the form: [Type] HostName AdapterAddress [Route] [temp] [pub] where `Type` Specifies the type of hardware address. If the address type is specified when invoking arp from the command line, it should not be specified in the file entries. Otherwise, it should be specified in each file entry. Valid hardware address types are: `ether` for an Ethernet interface `802.3` for an 802.3 interface `fddi` for a Fiber Distributed Data interface `802.5` for a Token-Ring interface `HostName` Specifies the remote host. `AdapterAddress` Specifies the hardware address of the adapter for this host as 6 hexadecimal bytes separated by colons. Use the netstat -v command to display the local hardware address. `Route` Specifies the route for a Token-Ring interface or Fiber Distributed Data Interface (FDDI) as defined in the Token-Ring or FDDI header. `temp` Specifies that this ARP table entry is temporary. The table entry is permanent if this argument is omitted. `pub` Specifies that this table entry is to be published, and that this system will act as an ARP server responding to requests for `HostName`, even though the host address is not its own. Note: The -f flag is not supported for ATM.
-s	Used as [ -t ifType ] -s Type HostName AdapterAddress [ Route ] [ temp ] [ pub ] Creates an ARP entry of the type specified by the Type variable for the host specified by the HostName variable with the adapter address specified by the AdapterAddress variable. The adapter address is given as 6 hexadecimal bytes separated by colons. The line must be in the following format: Type HostName AdapterAddress [Route] [temp] [pub] where the Type, HostName, AdapterAddress, Route, temp, and pub parameters have the same purpose and definitions as the parameters for the -f flag. Used as -t atm -s Type HostName AdapterAddress [ temp ] Creates a SVC type of ARP entry for the remote host, specified by the HostName variable, with the ATM address specified by the ATMAddress variable. The ATM address is given as 20 hexadecimal bytes separated by colons. Creation of this entry causes this IP station to not use ARP server mechanism to resolve IP addresses. Used as -t atm -s Type pvc vpi:vci { HostName \| if ifName } [ no-llc ] [ no-arp ] [ temp ] Creates a PVC type of ARP entry for the remote host, specified by the HostName variable, with the PVC specified by the vpi:vci. Either destination Hostname or the local ifname needs to be specified. The no-llc flag is used to indicate that LLC/SNAP encapsulation will not be used on this virtual circuit, in this case, the destination Hostname needs to be specified. The no-arp flag is used to indicate that ARP protocol will not be used on this virtual circuit, in this case, the destination Hostname needs to be specified. The temp parameter specifies that this ARP table entry is temporary, the table entry is permanent if this argument is omitted.
-t ifType	The -t iftype flag is used to indicate the type of Network interface. It is optional for the following types of interfaces: et for IEEE 802.3 Ethernet (inet, xns) tr for Token-Ring (inet, xns) xt for X.25 (inet) sl for serial line IP (inet) lo for loopback (inet) op for serial (inet) The -t atm flag is required for the following interfaces: at for ATM

Examples

To add a single entry to the arp mapping tables until the next time the system is restarted, type:
```
arp -s 802.3 host2 0:dd:0:a:85:0 temp
```
To delete a map table entry for the specified host with the arp command, type:
```
arp   -d   host1 flag
```
To display arp entries for atm host host1 , type:
```
arp -t atm -a host1 
```
To add a PVC arp entry for atm host host2, type:
```
arp   -t atm   -s atm pvc 0:20 host2 
```
To add a PVC arp entry for an interface at0, type:
```
arp   -t atm   -s atm pvc 0:20 if at0
```

Related Information

The ifconfig command, netstat command.

The inetd daemon.

TCP/IP Protocols in AIX 5L Version 5.2 System Management Guide: Communications and Networks.