My system is Windows 2000 and I’m on dialup. I noticed that as soon as the connection to my ISP is established there is communication activity (as indicated by the twin-screen icon in the systems tray bottom r.h. corner). It lasts for perhaps a minute. I tried to see what causes it but Comodo showed nothing communicating at that time. So I set Comodo to Block All and surprisingly that had no effect: the communication continued.
How is it that there can be communication to and from my machine that Comodo isn’t aware of and isn’t able to prevent even with Comodo set to Block All?
I believe that BLOCK ALL applies to traffic attempting to get in or out via the network adaptor/s. Applications can still run and there may still be alerts, but inbound and outbound traffic is blocked from getting to or from the internet/LAN.