Thought I'd post this tip since I was unable to reach my Linux box via NR when the firewall was up.
I'm using Firestarter as my gui front end on Ubuntu 12.04. If you're not using Firestarter you may be able to find a similar solution. If you're conversant with configuring firewall rules you should have no problem.
OK, Firestarter uses this file for rules to be executed before the Firestarter generated rules:
Code:
/etc/firestarter/user-pre
Initially, this file is empty. Simply edit it and add the following two lines:
Code:
$IPT -A INPUT -i nrtap+ -j ACCEPT
$IPT -A OUTPUT -o nrtap+ -j ACCEPT
Restart the firewall and you're good to go.
Hope this helps someone.
EE