IP tables rules for l4d2 server

iptables.rules

*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p udp -m udp --dport 27000:27030 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 27014:27050 -j ACCEPT
-A INPUT -p udp -m udp --dport 4380 -j ACCEPT
-A INPUT -p udp -m udp --dport 3478 -j ACCEPT
-A INPUT -p udp -m udp --dport 4379 -j ACCEPT
-A INPUT -p udp -m udp --dport 4380 -j ACCEPT
-A INPUT -j DROP
-A OUTPUT -p tcp -m tcp --sport 22 -j ACCEPT
COMMIT