Programs are urged to 224.0.0.2?

Question

firewall

We are talking about Windows 7. For several days, a variety of programs, mostly asking for IGMP on 224.0.0.2 at startup, I just know what it is, but I don’t understand what they all needed so sharply there. Why, suddenly, for years, no one needed to go there, and then once and everyone is breaking.
Explorer, firefox, TheBat, sidebar and someone else was noticed.
And one more thing on the subject. I can't understand this at all. I have my own server, the mail server works on it. There are several mailboxes configured in TheBat that communicate with this server. So, today Dropbox asked for this server on port 110. How can this be? How did Dropbox even know about this server.
How exciting it was :)

Answer 1

Multicast

224.0.0.2 - all LAN routers

Answer 2

People, don't scare me so sharply, I have financial information on my computer and in general you can find a lot of interesting things. Think you need to run to change passwords? I didn’t seem to open any links, I didn’t launch any applications in the mail, I’m not sitting under the admin account.

Answer 3

IGMP on 224.0.0.2

join? Run Wireshark, find out which group is being subscribed/unsubscribed to.