Connection loosing at some places - caused by firewall

Dear Members!

Windows 10, PGSQL 9.4 and 9.6 (Debian with SSL, and Windows without it - it
doesn't matter).

When I (or my boss) work(s) at home, I got connection lost errors from
PGAdmin (3/4) or from other applications too.

server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.

PGAdmin, EMS PostgreSQL manager, Navicat for PGSQL, and psql too.

When minimum 5 minutes passed after the last request (select, insert, or
any communication what I did) the connection lost.

The keepalive timer is 10 minutes in the server - so it is not the source
of the problem.

I tried to set keepalive in the clients (EMS, Navicat called ping) to lower
- no effect.

When I did any request in my side before the 5 minutes "limit" passed, I
got a new 5 minutes.

It seems to be libpq.dll applications need traffic (started by the client)
in 5 minute periods to keep the connection.

In the office I don't have this limitation.

My colleauge can work at home without time limit, and he has same Internet
Provider as mine.

It's not PGSQL server based.
When I use VPN connection from home to reach office PG server, I also got
this problem.
From the office I can use same IP, same server without problem.

I checked the router, I disabled all things - nothing happened.

*I disabled my firewall at home - the problem vanished!!!*

And: if I use a secondary test computer (also Windows 10, PGAdmin III) - it
works at home!!!

I very-very wondered because it seems to be computer firewall problem.
I tried to use wifi and direct cable - no differents, so network card could
be eliminated from the "problem sources" list.

It's very interesting!
The firewall could make differents between networks and limits these
packages timeout to 5 minutes? Hmmm...

I made an exception to the firewall - nothing happened.

I know this is not Windows Admin list, but you may experienced same
problem, or you have idea about what to do.

This is become important for us because one of my customer have same
problem, and we don't know the solution...

What is your opinion about it?

Thanks
dd