iptables is installed by default. We have an article on iptables: https://www.digitalocean.com/community/articles/how-to-set-up-a-firewall-using-ip-tables-on-ubuntu-12-04

It's for Ubuntu 12.04 but it should work on Debian as well.

Thank you very much!

I'll have a look at it :)

Question:

Should there be applied first or last when i have made some rulesets

iptables -F INPUT
iptables -F FORWARD
iptables -F OUTPU

The thing im after is stopper some dosw attack (if occur) still allow the connection that is allready made. and allow the following ports : 5022/80

Nevermind the reply :)