(Similar to my previous question , but addressing a separate aspect which has gone unanswered.) I've seen this on my Windows 7 computer, and searches have turned up others in Vista/7 who have seen the same. However, I've not yet found (or perhaps have just missed) a good explanation for this. These two addresses are static in my ARP table, but I don't know what put them there: 224.0.0.22 01-00-5e-00-00-16 static 224.0.0.252 01-00-5e-00-00-fc static I know the ARP table gets updated whenever my computer talks to another system on the subnet, but those entries get added as "dynamic". "Static" entries only get added either by direct user intervention, or by software acting on behalf of the user. Is there any software known to add these particular addresses, or similar ones, to the table? Is this a normal part of the Windows 7/Vista installation, or would the entries have been added by other software along the way? Answer 224.0...