Iptables

Basic Rules
iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A INPUT -p tcp --dport 22 -j ACCEPT iptables -A INPUT -p tcp --dport 80 -j ACCEPT iptables -A INPUT -p tcp --dport 443 -j ACCEPT iptables -A INPUT -p tcp --dport 5060 -j ACCEPT iptables -A INPUT -p udp --dport 5060 -j ACCEPT iptables -A INPUT -p tcp --dport 5080 -j ACCEPT iptables -A INPUT -p udp --dport 5080 -j ACCEPT iptables -A INPUT -p udp --dport 16384:32768 -j ACCEPT iptables -A INPUT -p udp --dport 1194 -j ACCEPT iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT ACCEPT

Optional Allow ICMP
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT

Friendly Scanner
Rules to block not so friendly scanner iptables -I INPUT -j DROP -p tcp --dport 5060 -m string --string "friendly-scanner" --algo bm iptables -I INPUT -j DROP -p tcp --dport 5080 -m string --string "friendly-scanner" --algo bm iptables -I INPUT -j DROP -p udp --dport 5060 -m string --string "friendly-scanner" --algo bm iptables -I INPUT -j DROP -p udp --dport 5080 -m string --string "friendly-scanner" --algo bm

Show iptable rules
sudo iptables -L -v

Show line numbers
iptables -L -v --line-numbers

Delete a line
Delete line 2 iptables -D INPUT 2

Block IP address
iptables -I INPUT -s 62.210.245.132 -j DROP

Save Changes
Debian / Ubuntu apt-get install iptables-persistent service iptables-persistent save