# 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	Queries 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 - 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 stack is enabled. ## Example Run the **arp** command. ARP cache table: ``` OHOS # arp Address HWaddress Iface Type 192.168.1.10 E6:2B:99:2C:4B:20 eth0 static ``` **Table 2** Output description

Parameter	Description
Address	IPv4 address of a network device.
HWaddress	MAC address of a network device.
Iface	Name of the port used by the ARP entry.
Type	Indicates 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.