Linux in a Nutshell, Fourth Edition

Name

arp

Synopsis

                  arp [options]

TCP/IP command. Clear, add to, or dump the kernel’s Address Resolution Protocol (ARP) cache (/proc/net/arp). ARP is used to translate protocol addresses to hardware interface addresses. Modifying your ARP cache can change which interfaces handle specific requests. ARP cache entries may be marked with the following flags: C (complete), M (permanent), and P (publish). In kernels before 2.2, a published entry was used for creating an ARP proxy, a technique by which one system can act as a gateway to another system on the same subnet. While arp can create a proxy for a single system, subnet proxies are now handled by the arp kernel module. See the Linux 2.4 Advanced Routing HOWTO for details. We have retained the subnet proxy information here for older kernels.

Options

host option arguments may be given as either a hostname or an IP address. When using the -D option, they may also be given as a hardware interface address (e.g., eth0, eth1).

-a [hosts], --display [hosts]

Display entries for hosts or, if none are specified, all entries.

-d host, --delete host

Remove the specified host’s entry.

-D, --use-device

Use the hardware address associated with the specified interface. This may be used with -s when creating a proxy entry.

-d host [pub], --delete host [pub]

Remove host’s entry. To delete a proxy entry, use the pub argument and specify the interface associated with the proxy using -i.

-f file, --file file

Read entries from file and add them.

-H type,