Iptables

Applicable Iptables rules in the installation.

Basic Rules

iptablesF
iptablesA INPUT -p icmp --icmp-type echo-request -j ACCEPT
iptablesA OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT
iptablesA INPUT -i lo -j ACCEPT
iptablesA INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptablesA INPUT -p tcp --dport 22 -j ACCEPT
iptablesP INPUT DROP
iptablesP FORWARD DROP
iptablesP OUTPUT ACCEPT
iptablesA INPUT -p udp -m udp --dport 5060 -j ACCEPT
iptablesA INPUT -p udp -m udp --dport 10000:20000 -j ACCEPT
iptablesA INPUT -p tcp -m tcp --dport 80 -j ACCEPT

Optional Rules

OPENVPN: iptables -A INPUT -p udp --dport 1194 -j ACCEPT
ICMP: iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
IAX: iptables -A INPUT -p udp -m udp --dport 4569 -j ACCEPT
HTTPS: iptablesA INPUT -p tcp -m tcp --dport 443 -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

Optional

iptables -I INPUT -j DROP -p tcp --dport 5060 -m string--string "VaxSIPUserAgent" --algo bm
iptables -I INPUT -j DROP -p udp --dport 5060 -m string --string "VaxIPUserAgent" --algo bm
iptables -I INPUT -j DROP -p udp --dport 5080 -m string --string "VaxSIPUserAgent" --algo bm
iptables -I INPUT -j DROP -p tcp --dport 5080 -m string --string "VaxIPUserAgent" --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

apt-get install iptables-persistent service iptables-persistent save dpkg-reconfigure iptables-persistent