How to check ARP entry?

To check the ARP (Address Resolution Protocol) entry, you can use the command prompt in Windows.

Checking ARP Entries in Windows

Here's a step-by-step guide on how to view the ARP table using the command prompt:

1. Open Command Prompt as Administrator:
   • In the “Open” textbox, type “cmd”.
   • Select "Run as administrator".
   • If a User Account Control (UAC) prompt appears, select "Yes".
2. View the ARP Table:
   • Type the command arp -a in the command prompt window.
   • Press the Enter key.

After executing the command, the ARP table will be displayed. This table shows the mapping between IP addresses and their corresponding MAC addresses for devices on your local network. Each entry includes:

• Internet Address: The IP address of a device on your network.
• Physical Address: The MAC address associated with the IP address.
• Type: Indicates whether the ARP entry is dynamic or static.

Understanding the ARP Table

• Dynamic entries are learned automatically when devices communicate with each other.
• Static entries are manually configured by the administrator.
• ARP entries are cached, and may expire after a period of inactivity.

Example Output

A typical ARP table output might look like this:

Interface: 192.168.1.101 --- 0x2
  Internet Address      Physical Address      Type
  192.168.1.1         00-aa-bb-cc-dd-ee    dynamic
  192.168.1.100        ff-11-22-33-44-55   dynamic

Practical Insight

• You can use the arp -d command followed by an IP address to delete a specific entry from the table. For example, arp -d 192.168.1.100.
• You can use arp -d * command to delete all entries.
• Using the arp -s command, you can add static ARP entries. This command requires the IP address and the MAC address to be specified.
• The arp command with no arguments just shows the syntax and options for the arp command.