Which ports should I open for apt-get to work?

Question

I installed Webmin, and then set up the firewall like this:

INPUT
SSH port ALLOWED
Webmin port ALLOWED
HTTP port (80) ALLOWED
DROP EVERYTHING ELSE

FORWARDING
no rules

OUTPUT
no rules

If I remove DROP EVERYTHING ELSE from INPUT, everything works.

However, when that rule is added, apt-get doesn't work, and I can't ping or traceroute anything.

Even with DROP EVERYTHING ELSE enabled, Webmin, HTTP and SSH still work.

Which ports should I unblock to get apt-get working and allowed connecting to other domains from within the server?

Thanks

Solution

Make sure you accept also connection originated from inside. With iptables:

iptables -A INPUT -m state --state ESTABLISHED -j ACCEPT

With Webmin, allow

Connection states EQUALS Existing Connection

Comments

[Admin]

Try port 22 or 21

[Juan Furattini]

Hello, this works fine.Thanks! P.S. to do this on Webmin (for anyone who finds this on Google) you need to choose "Connection states EQUALS Existing Connection"