iptables - allow connections only from LAN
Solution 1:
iptables -A INPUT -p tcp -m state --state NEW --source 192.168.0.1/24 --dport 22 -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j DROP
iptables -A INPUT -p tcp -m state --state NEW --source 192.168.0.1/24 --dport 22 -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j DROP