arp

Command Function

Hosts on an Ethernet communicate with each other using MAC addresses. IP addresses must be converted into MAC addresses to enable communication between hosts on a LAN (Ethernet). To achieve this purpose, the host stores a table containing the mapping between IP addresses and MAC addresses. This table is called an Address Resolution Protocol (ARP) cache table. Before sending an IP packet to a LAN, the host looks up the destination MAC address in the ARP cache table. The ARP cache table is maintained by the TCP/IP stack. You can run the arp command to view and modify the ARP cache table.

Syntax

arp

arp [-i IF] -s IPADDR HWADDR

arp [-i IF] -d IPADDR

Parameters

Table 1 Parameter description

Parameter	Description	Value Range
No parameter	Prints the content of the ARP cache table.	N/A
-i IF	Specifies the network port. This parameter is optional.	N/A
-s IPADDR HWADDR	Adds an ARP entry. The second parameter is the IP address and MAC address of the other host on the LAN.	N/A
-d IPADDR	Deletes an ARP entry.	N/A

Usage Guidelines

The arp command is used to query and modify the ARP cache table of the TCP/IP stack. If ARP entries for IP addresses on different subnets are added, the protocol stack returns a failure message.
This command can be used only after the TCP/IP protocol stack is enabled.

Example

Run arp.

ARP cache table information:

OHOS # arp
Address                 HWaddress               Iface       Type
192.168.1.10            E6:2B:99:2C:4B:20       eth0        static

Table 2 Parameter description

Parameter	Description
Address	IPv4 address of the network device.
HWaddress	MAC address of the network device.
Iface	Name of the port used by the ARP entry.
Type	Whether the ARP entry is dynamic or static. A dynamic ARP entry is automatically created by the protocol stack, and a static ARP entry is added by the user.