I have Windows 7 and have noticed that my system is using port 4 to connect to a lot of different IP addresses. When it connects to them it is not for very long before it moves to another IP address.
One night I sat and wrote down as many as I could and started checking whois to see where they were and they were from all over the world. I don't understand this.
When I did a search on the net with this question. The only info I could come up with was, that port 4 is used by the US Army and a list of port assignments listed it as "unassigned". If anyone has any clues to what is going on... I would greatly appreciate any info I could get.