Here's another of the close voters. I agree that the reason given seems weird - though it's unfortunately easy to click on the wrong the close vote reason and then you can't easily go back and fix it.
However, looking at the question, it's the end of it that jumps out at me:
then when I run apt-get I obtain:
core:~# apt-get update 0% [Connecting to ftp.us.debian.org] [Connecting to security.debian.org] > [Conne
and it stalls. What rules I need to configure to make it works.
The specific things that make me want to burninate this question is:
Lack of firewall logs. The first thing to do, which every sysadmin should know, is look at the logs. You don't do trial-and-error, you do trial-and-verify.
The words "What rules I need to configure to make it works." If the question had been "How do I figure out what rules I need to make it works" I would probably have left a comment containing the previous point, and it would've been solved.
However, I think if I saw it today, I might punt it over to Unix/Linux instead; they're much more welcoming to newbies - and rightly so; that site isn't restricted to professionals.