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arp(8)
NAME
  arp - Displays and controls Address Resolution Protocol (ARP) tables

SYNOPSIS
  /usr/sbin/arp [-u] hostname

  arp -a [-u] [-n] [system]

  arp -d hostname

  arp -f filename

  arp -g hostname

  arp -s [-u] hostname hardware_addr [temp] [pub] [trail]

FLAGS
  -a  Displays all of the current ARP entries.

  -d hostname
      Deletes the entry for hostname if the user issuing the command has
      superuser authority.

  -f filename
      Reads entries from filename and adds those entries to the ARP tables.
      Use of this flag requires superuser privilege.  Entries in the file
      have the following format:


	   hostname hardware_addr [temp] [pub] [trail]

      Fields in this format are as follows:

      hostname
	  Specifies the remote host identified by the entry.

      hardware_addr
	  Specifies the hardware address of the remote host.  The address is
	  given as 6 hexadecimal bytes separated by colons.

      temp
	  Specifies that this ARP table entry is temporary.  When this
	  argument is not used, the table entry is permanent.

      pub Indicates that the table entry will be published and that the
	  current system will act as an ARP server, responding to requests
	  for hostname even though the host address is not its own.

      trail
	  Indicates that the trailer encapsulation may be sent to this host.

  -n  Displays numeric IP addresses and hardware addresses only.  When this
      flag is not specified, arp displays hostnames, numeric IP addresses,
      and hardware addresses.

  -g hostname
      Sends a gratuitous ARP packet.  The hostname can be a local host name,
      alias, or IP address.

  -s hostname hardware_addr [temp] [pub] [trail]
      Creates a single ARP entry for hostname.	Use of this flag requires
      superuser privilege.  The arguments are explained in the discussion of
      the -f flag.

  [-u]
      Displays the MAC address in noncanonical form with address bytes
      reversed and separated by a colon character (:). By default, all
      addresses are displayed in canonical form with address bytes separated
      by the hyphen character (-).

      When used with the -s flag, this indicates that the hardware_addr is in
      noncanonical form.

DESCRIPTION
  The arp command displays or modifies the current ARP entry for the host
  specified by hostname.  The host may be specified by name or number, using
  Internet dot notation.

  With no flags, the program displays the current ARP entry for hostname.

  The ARP tables can be displayed by any user, but only the superuser can
  modify them.

EXAMPLES
   1.  To display the ARP address-mapping tables for the local host that has
       one interface defined, enter:


	    arp -a

	    alpha1.dec.com (16.181.20.2) at 08-00-2b-2c-f5-31
	    alpha2.dec.com (16.100.21.20) at 08-00-2b-3c-2d-fd

   2.  To add a single entry for the remote host laszlo to the ARP mapping
       tables temporarily, enter:


	    arp -s laszlo 08:00:2b:0f:44:23 temp

       The address is considered canonical even though the bytes are
       separated by colons. For input, the arp command does not use the colon
       (:) and hyphen (-) characters to indicate whether the address is
       canonical or noncanonical.

       Note that you must have superuser authority to execute this command.

   3.  To add a single entry for the remote host laszlo to the ARP mapping
       tables temporarily, enter:


	    arp -u -s laszlo 10:00:d4:f0:22:c4 temp

       The -u flag indicates the address is noncanonical. Note that you must
       have superuser authority to execute this command.

   4.  To add multiple entries to the ARP mapping tables from the file
       newentries, enter:


	    arp -f newentries

       Note that you must have superuser authority to execute this command.

FILES
  /usr/sbin/arp
	     Specifies the command path.

RELATED INFORMATION
  Commands: netstat(1), ifconfig(8)

  Protocols: arp(7)

  Specifications:  RFC 826

Index for Section 8

Alphabetical listing for A

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