arpd – Collect gratuitous ARP information

The arpd command is used to collect gratuitous Address Resolution Protocol (ARP) information. ARP is a protocol used to map an IP address to a physical (MAC) address. Gratuitous ARP is a type of ARP packet that is sent by a device to update its own ARP cache and the ARP caches of other devices on the network. The arpd command collects and logs this information for analysis and troubleshooting purposes.


The arpd command can be used to collect gratuitous ARP information by running the command with the appropriate options and arguments. The basic syntax for the command is as follows:

arpd [options] [interface]

Where options are the various command options and interface is the network interface to collect ARP information on.


Here are some examples of how to use the arpd command:

arpd -i eth0

This command collects gratuitous ARP information on the eth0 network interface.

arpd -i eth0 -d /var/log/arpd.log

This command collects gratuitous ARP information on the eth0 network interface and logs the information to the /var/log/arpd.log file.

Use cases

The arpd command can be used in a variety of situations, including:

  • Troubleshooting network connectivity issues
  • Analyzing network traffic
  • Monitoring network activity


Here are the available options for the arpd command:

Option Description
-d FILE Log output to FILE
-i IFACE Listen on network interface IFACE
-n Do not resolve IP addresses to hostnames
-t SECONDS Time to live for ARP entries in seconds
-v Verbose output

Troubleshooting tips

Here are some tips for troubleshooting common issues with the arpd command:

  • Make sure the correct network interface is specified with the -i option.
  • Check the log file specified with the -d option for any errors or issues.
  • Verify that the arpd daemon is running and functioning properly.


  • The arpd command requires root privileges to run.
  • Gratuitous ARP packets are typically sent by devices when they come online or change network configurations.
  • The arpd command can be used in conjunction with other network analysis tools, such as Wireshark, for more detailed analysis of network traffic.