You may have other services you want to accept connections to, we can add more rules for any port with a simple command just replace with the type of connection TCP, or UDP. Sudo iptables -A INPUT -p tcp -m tcp -dport 993 -j ACCEPT IMAP server sudo iptables -A INPUT -p tcp -m tcp -dport 143 -j ACCEPT Sudo iptables -A INPUT -p tcp -m tcp -dport 995 -j ACCEPT POP3 server sudo iptables -A INPUT -p tcp -m tcp -dport 110 -j ACCEPT Sudo iptables -A INPUT -p tcp -m tcp -dport 465 -j ACCEPT SMTP server sudo iptables -A INPUT -p tcp -m tcp -dport 25 -j ACCEPT We could go more in depth and allow connections only from certain IPвЂ™s.ДЄllow SSH connections (*Important if you want to use SSH to manage your Pi*) sudo iptables -A INPUT -p tcp -m tcp -dport 22 -j ACCEPTДЄllow HTTP server sudo iptables -A INPUT -p tcp -m tcp -dport 80 -j ACCEPTДЄllow HTTPS server sudo iptables -A INPUT -p tcp -m tcp -dport 443 -j ACCEPT So I will list the service then the command to open the port. Using the above rules we block some basic attacks we will start adding rules to open specific ports we will use. Sudo iptables -A INPUT -p tcp -tcp-flags ALL ALL -j DROPДЇirst please note all commands use sudo, you need higher privileges to add firewall rules. Sudo iptables -A INPUT -p tcp ! -syn -m state -state NEW -j DROP Sudo iptables -A INPUT -p tcp -tcp-flags ALL NONE -j DROP

Firewall builder raspberry pi