arp(1M) 						  System Administration Commands						   arp(1M)

NAME

       arp - address resolution display and control

SYNOPSIS

       arp hostname

       arp -a [-n]

       arp -d hostname

       arp -f filename

       arp -s hostname ether_address [temp] [pub] [trail]
	    [permanent]

DESCRIPTION

       The arp program displays and modifies the Internet-to-MAC address translation tables used by the address resolution protocol (see arp(7P)).

       With  no flags, the program displays the current ARP entry for hostname. The host may be specified by name or by number, using Internet dot
       notation.

       Options that modify the ARP translation tables (-d, -f, and -s) can be used only when the invoked command  is  granted  the  sys_net_config
       privilege. See privileges(5).

OPTIONS

       -a    Display all of the current ARP entries. The definition for the flags in the table are:

	     d	  Unverified;  this  is  a  local  IP  address	that  is currently undergoing Duplicate Address Detection. ARP will not respond to
		  requests for this address until Duplicate Address Detection completes.

	     o	  Old; this entry is aging away. If IP requests it again, a new ARP query will be generated. This state is used for detecting peer
		  address changes.

	     y	  Delayed; periodic address defense and conflict detection was unable to send a packet due to internal network use limits for non-
		  traffic-related messages (100 packets per hour per interface). This occurs  only  on	interfaces  with  very	large  numbers	of
		  aliases.

	     A	  Authority; this machine is authoritative for this IP address. ARP will not accept updates from other machines for this entry.

	     L	  Local; this is a local IP address configured on one of the machine's logical interfaces. ARP will defend this address if another
		  node attempts to claim it.

	     M	  Mapping; only used for the multicast entry for 224.0.0.0

	     P	  Publish; includes IP address for the machine and the addresses that have explicitly been  added  by  the  -s	option.  ARP  will
		  respond to ARP requests for this address.

	     S	  Static; entry cannot be changed by learned information. This indicates that the permanent flag was used when creating the entry.

	     U	  Unresolved; waiting for ARP response.

	     You  can use the -n option with the -a option to disable the automatic numeric IP address-to-name translation. Use arp -an or arp -na
	     to display numeric IP addresses. The arp -a option is equivalent to:

	       # netstat -p -f inet

	     ...and -an and -na are equivalent to:

	       # netstat -pn -f inet

       -d    Delete an entry for the host called hostname.

	     Note that ARP entries for IPMP (IP Network Multipathing) data and test addresses are  managed  by	the  kernel  and  thus	cannot	be
	     deleted.

       -f    Read the file named filename and set multiple entries in the ARP tables. Entries in the file should be of the form:

	       hostname MACaddress [temp] [pub] [trail] [permanent]

	     See the -s option for argument definitions.

       -s    Create  an  ARP  entry for the host called hostname with the MAC address MACaddress. For example, an Ethernet address is given as six
	     hexadecimal bytes separated by colons. The entry will not be subject to deletion by aging unless the word temp is	specified  in  the
	     command.  If  the	word  pub is specified, the entry will be published, which means that this system will respond to ARP requests for
	     hostname even though the hostname is not its own. The word permanent indicates that the system will not accept  MAC  address  changes
	     for hostname from the network.

	     Solaris does not implement trailer encapsulation, and the word trail is accepted on entries for compatibility only.

	     arp  -s can be used for a limited form of proxy ARP when a host on one of the directly attached networks is not physically present on
	     a subnet. Another machine can then be configured to respond to ARP requests using arp -s. This is useful in certain  SLIP	configura-
	     tions.

	     Non-temporary proxy ARP entries for an IPMP (IP Network Multipathing) group are automatically managed by the kernel. Specifically, if
	     the hardware address in an entry matches the hardware address of an IP interface in an IPMP group, and the IP address is not local to
	     the  system,  this  will  be regarded as an IPMP proxy ARP entry. This entry will have its hardware address automatically adjusted in
	     order to keep the IP address reachable so long as the IPMP group has not entirely failed.

	     ARP entries must be consistent across an IPMP group. Therefore, ARP entries cannot be associated with individual underlying IP inter-
	     faces in an IPMP group, and must instead be associated with the corresponding IPMP IP interface.

	     Note that ARP entries for IPMP data and test addresses are managed by the kernel and thus cannot be changed.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ifconfig(1M), netstat(1M), attributes(5), privileges(5), arp(7P)

SunOS 5.11							    5 Jan 2009								   arp(1M)