nbdgram (138): are continuous requests between LAN PC normal?


I’m a comodo noob!

Some days ago I installed this v3 on my pc; had the chance to try v2 on my family pc last year, and it was impressive (although a bit annoying).

Here’s a brief description of my LAN:

  • mule pc, permanently connected to WAN
  • my pc, equipped with Comodo v3
  • family pc

The point of view is my pc, where I installed Comodo v3.
After its installation, before setting it up in a good manner, I continued to receive warnings like this:

where the Remote address shown was the one of my mule PC, connected permanently.
What feels like a strange thing to me, is that these warnings showed up always, also if I wasn’t directly connected (VNC, windows explorer ) to that pc
Sometime, same warnings appeared with the remote address of my family pc (when someone did turn on it)

My first question is:
is it normal that two pc, just because are sitting on the same LAN, change information between each other, also if they’re not involved in sharing activities?

then, after days of multiple warnings, I went to configure my comodo v3.
In one of the many guide I red, I found to block 135-139, 445 and 500 ports for security issues.
After that, of course I did not receive any more pop-up.

But my second question is:
if the answer of the first question is YES, thus it is normal and maybe necessary that 2 PC on the same LAN communicate also out of user’s willing, why if I block those port everything is fine and moreover I got no log??

thank you for the answers!