What is this “Thing” on my network?

Question

I was using AMD's magic packet utility to build a list of computers to do wake-on-lan and it found these entries:

224.0.0.22  igmp.mcast.net	01-00-5e-00-00-16
224.0.0.252 *NameNotFound*	01-00-5e-00-00-fc
239.255.255.250 *NameNotFound*	01-00-5e-7f-ff-fa

First of all, I'm not sure why it would find these. They're not in the subnet I provided. I've never heard of them before; if they're reserved or not.

Feel free to offer a more descriptive title to this question and delete this comment. I'm not sure how to describe what I'm seeing, google only makes fun of me when I ask it this.

Answer 1

All perfectly normal to see in a modern network. They are all IPv4 multicast addresses. Here's a brief breakdown and you can read up in depth on your own:

224.0.0.22 - IGMP - http://en.wikipedia.org/wiki/224.0.0.22

224.0.0.252 - LLMNR - http://en.wikipedia.org/wiki/Link-local%5FMulticast%5FName%5FResolution

239.255.255.250 - SSDP - http://en.wikipedia.org/wiki/Simple%5FService%5FDiscovery%5FProtocol

Answer 2

Those are multicast addresses. Multicast addresses are used when a single packet is intended to be sent to multiple recipients. Refer to http://www.iana.org/assignments/multicast-addresses/ for a list of service what each address typically corresponds to.

Answer 3

all look like multicast packets to me;

• 224.0.0.22 - IGMP [ maybe you have some multicast-enabled media player ].
• 224.0.0.252 - Link-local Multicast Name Resolution
• 239.255.255.250 - upnp - can be your router or client machine.