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What are the purposes of the addresses in this ARP table?

I notice that ANY computer that I go to, if I do a arp -a command from a command line, I receive a reply back of It returns as a physical address and is labeled as static. I get this from work computers, home computers, everywhere! So what is it exactly for? Where does it point to?

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3 Answers 3

15 is a multicast-address.

Multicast is thought for ip addresses which can be "subscribed" to. A multicast IP can be subscribed to by multiple network interfaces and will be routed by routers in a special way. This way you can create an IP address with multiple recipients.

An example would be a peer to peer chat where everybody, instead of sending a message to every other computer, send them to the multicast address where the routers take over the work of distributing the data to all the correct addresses.

Another unlikely real world example: Let's say there's a special "copy" mailing address registered in the post office. All mail sent to this address will be opened, all pages copied and sent to 5 different addresses.


The address is used for the IGMPv3 protocol.

This protocol is used by hosts to manage its multicast insterests. You can have more information on the Wikipedia page linked above.

The address 01:00:5e:00:00:16 is the correspondent layer 2 address. You can read here and here about how multicast ip addresses are converted to MAC multicast addresses. And you can use this tool if you want to try it.

  • Sory. My first answer was wrong since I've read instead of
    – fmanco
    Jun 26, 2012 at 13:50
  • 2
    Tool link is down.............
    – Pacerier
    Feb 12, 2015 at 8:49
  • This should be marked as the correct answer. The other answer simply states what captain obvious would say that it is a multicast address.
    – Brain2000
    Aug 18, 2022 at 17:56

It is used for IGMPv3 Reporting. See also here (translated from polish)

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