to be honest, that's not much of a configuration,
but i'm up for putting our heads together to come up with a good basic rule-set,
maybe even include it into obarun as a default?
my starting configuration: (feel free to point out any mistakes/improve)
# Generated by iptables-save v1.4.21 on Wed Oct 14 21:55:40 2015
*filter
:INPUT DROP [190:10117]
:FORWARD DROP [0:0]
:OUTPUT DROP [6478:808942]
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state INVALID -j LOG --log-prefix "INVALID DROP INP"
-A INPUT -m state --state INVALID -j DROP
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p udp -m udp --dport 55555 -m state --state NEW -j ACCEPT
-A INPUT -p tcp -m tcp --dport 55555 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT
-A INPUT -i [!]lo -j LOG --log-prefix "DROP INP"
-A OUTPUT -o lo -j ACCEPT
-A OUTPUT -m state --state INVALID -j LOG --log-prefix "DROP INVALID OUT"
-A OUTPUT -m state --state INVALID -j DROP
-A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 21 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 22 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 25 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 43 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 80 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 443 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 6697 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A OUTPUT -p udp -m udp --dport 53 -m state --state NEW -j ACCEPT
-A OUTPUT -p udp -m udp --sport 55555 -m state --state NEW -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 55555 --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j ACCEPT
-A OUTPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT
-A OUTPUT -o [!]lo -j LOG --log-prefix "DROP OUT"
COMMIT
# Completed on Wed Oct 14 21:55:40 2015
basically i'm dropping all connections by default then allowing basic services like ftp/http/https/ssh/irc (6697), some basic ping response, and torrent on port 55555,
and doing some logging, if you have questions about any specific rule, ask.