ARP(8)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Linux System Administrator’s Manual\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ARP(8)<\/p>\n
NAME<\/p>\n
arp – manipulate the system ARP cache<\/p>\n
SYNOPSIS<\/p>\n
arp [-vn] [-H type] [-i if] [-ae] [hostname]<\/p>\n
arp [-v] [-i if] -d hostname [pub]<\/p>\n
arp [-v] [-H type] [-i if] -s hostname hw_addr [temp]<\/p>\n
arp [-v] [-H type] [-i if] -s hostname hw_addr [netmask nm] pub<\/p>\n
arp [-v] [-H type] [-i if] -Ds hostname ifname [netmask nm] pub<\/p>\n
arp [-vnD] [-H type] [-i if] -f [filename]<\/p>\n
DESCRIPTION<\/p>\n
Arp manipulates or displays the kernel’s IPv4 network neighbour
\ncache. It can add entries to the table, delete one or display the
\ncurrent content.<\/p>\n
ARP stands for Address Resolution Protocol, which is used to find the
\nmedia access control address of a network neighbour for a given IPv4
\nAddress.<\/p>\n
MODES<\/p>\n
arp with no mode specifier will print the current content of the
\ntable. It is possible to limit the number of entries printed, by
\nspecifying an hardware address type, interface name or host address.<\/p>\n
arp -d address will delete a ARP table entry. Root or netadmin
\nprivilege is required to do this. The entry is found by IP address.
\nIf a hostname is given, it will be resolved before looking up the
\nentry in the ARP table.<\/p>\n
arp -s address hw_addr is used to set up a new table entry. The
\nformat of the hw_addr parameter is dependent on the hardware class,
\nbut for most classes one can assume that the usual presentation can
\nbe used.\u00a0 For the Ethernet class, this is 6 bytes in hexadecimal,
\nseparated by colons. When adding proxy arp entries (that is those
\nwith the publish flag set) a netmask may be specified to proxy arp
\nfor entire subnets. This is not good practice, but is supported by
\nolder kernels because it can be useful. If the temp flag is not
\nsupplied entries will be permanent stored into the ARP cache. To
\nsimplify setting up entries for one of your own network interfaces,
\nyou can use the arp -Ds address ifname form. In that case the
\nhardware address is taken from the interface with the specified name.<\/p>\n
OPTIONS<\/p>\n
-v, –verbose
\nTell the user what is going on by being verbose.<\/p>\n
-n, –numeric
\nshows numerical addresses instead of trying to determine
\nsymbolic host, port or user names.<\/p>\n
-H type, –hw-type type, -t type
\nWhen setting or reading the ARP cache, this optional parameter
\ntells arp which class of entries it should check for.\u00a0 The
\ndefault value of this parameter is ether (i.e. hardware code
\n0x01 for IEEE 802.3 10Mbps Ethernet).\u00a0 Other values might
\ninclude network technologies such as ARCnet (arcnet) , PROnet
\n(pronet) , AX.25 (ax25) and NET\/ROM (netrom).<\/p>\n
-a\u00a0\u00a0\u00a0\u00a0 Use alternate BSD style output format (with no fixed columns).<\/p>\n
-e\u00a0\u00a0\u00a0\u00a0 Use default Linux style output format (with fixed columns).<\/p>\n
-D, –use-device
\nInstead of a hw_addr, the given argument is the name of an
\ninterface.\u00a0 arp will use the MAC address of that interface for
\nthe table entry. This is usually the best option to set up a
\nproxy ARP entry to yourself.<\/p>\n
-i If, –device If
\nSelect an interface. When dumping the ARP cache only entries
\nmatching the specified interface will be printed. When setting
\na permanent or temp ARP entry this interface will be
\nassociated with the entry; if this option is not used, the
\nkernel will guess based on the routing table. For pub entries
\nthe specified interface is the interface on which ARP requests
\nwill be answered.
\nNOTE: This has to be different from the interface to which the
\nIP datagrams will be routed.\u00a0 NOTE: As of kernel 2.2.0 it is
\nno longer possible to set an ARP entry for an entire subnet.
\nLinux instead does automagic proxy arp when a route exists and
\nit is forwarding. See arp(7) for details. Also the dontpub
\noption which is available for delete and set operations cannot
\nbe used with 2.4 and newer kernels.<\/p>\n
-f filename, –file filename
\nSimilar to the -s option, only this time the address info is
\ntaken from file filename.\u00a0 This can be used if ARP entries for
\na lot of hosts have to be set up.\u00a0 The name of the data file
\nis very often \/etc\/ethers, but this is not official. If no
\nfilename is specified \/etc\/ethers is used as default.<\/p>\n
The format of the file is simple; it only contains ASCII text
\nlines with a hostname, and a hardware address separated by
\nwhitespace. Additionally the pub, temp and netmask flags can
\nbe used.<\/p>\n
In all places where a hostname is expected, one can also enter an IP
\naddress in dotted-decimal notation.<\/p>\n
As a special case for compatibility the order of the hostname and the
\nhardware address can be exchanged.<\/p>\n
Each complete entry in the ARP cache will be marked with the C flag.
\nPermanent entries are marked with M and published entries have the P
\nflag.<\/p>\n
EXAMPLES<\/p>\n
\/usr\/sbin\/arp -i eth0 -Ds 10.0.0.2 eth1 pub<\/p>\n
This will answer ARP requests for 10.0.0.2 on eth0 with the MAC
\naddress for eth1.<\/p>\n
\/usr\/sbin\/arp -i eth1 -d 10.0.0.1<\/p>\n
Delete the ARP table entry for 10.0.0.1 on interface eth1. This will
\nmatch published proxy ARP entries and permanent entries.<\/p>\n
FILES<\/p>\n
\/proc\/net\/arp
\n\/etc\/networks
\n\/etc\/hosts
\n\/etc\/ethers<\/p>\n
SEE ALSO<\/p>\n
rarp(8), route(8), ifconfig(8), netstat(8)<\/p>\n
AUTHORS<\/p>\n
Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>, Bernd Eckenfels
\n<net-tools@lina.inka.de>.<\/p>\n
COLOPHON<\/p>\n
This page is part of the net-tools (networking utilities) project.
\nInformation about the project can be found at
\n\u27e8http:\/\/net-tools.sourceforge.net\/\u27e9.\u00a0 If you have a bug report for
\nthis manual page, see \u27e8http:\/\/net-tools.sourceforge.net\/\u27e9.\u00a0 This page
\nwas obtained from the project’s upstream Git repository
\n(git:\/\/git.code.sf.net\/p\/net-tools\/code) on 2014-12-30.\u00a0 If you dis\u2010
\ncover any rendering problems in this HTML version of the page, or you
\nbelieve there is a better or more up-to-date source for the page, or
\nyou have corrections or improvements to the information in this
\nCOLOPHON (which is not part of the original manual page), send a mail
\nto\u00a0man-pages@man7.org<\/p>\n
net-tools\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2008-10-03\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ARP(8)<\/p>\n","protected":false},"excerpt":{"rendered":"
ARP(8)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Linux System Administrator’s Manual\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ARP(8) NAME arp – manipulate the system ARP cache SYNOPSIS arp [-vn] [-H type] [-i if] [-ae] [hostname] arp [-v] [-i if] -d hostname [pub] arp [-v] [-H type] [-i if] -s hostname hw_addr [temp] arp [-v] [-H type] [-i if] -s hostname hw_addr [netmask nm] pub arp [-v] [-H […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_sitemap_exclude":false,"_sitemap_priority":"","_sitemap_frequency":"","footnotes":""},"categories":[8],"tags":[],"class_list":["post-275","post","type-post","status-publish","format-standard","hentry","category-shell"],"a3_pvc":{"activated":false,"total_views":0,"today_views":0},"_links":{"self":[{"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/posts\/275","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=275"}],"version-history":[{"count":0,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=\/wp\/v2\/posts\/275\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=275"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=275"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.linuxboxen.dk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=275"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}