# 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. |