Firewall

UFW, or Uncomplicated Firewall, is an interface to iptables that is geared towards simplifying the process of configuring a firewall.

Install it as follows:

apt-get install ufw

After you have installed UFW, configure it as follows:

ufw default deny incoming
ufw default allow outgoing
ufw allow ssh
ufw allow 22
ufw allow 65000:65020/tcp
ufw allow 4000/tcp
ufw allow 4321/tcp
ufw allow 65000:65020/udp
ufw allow 8082/tcp
ufw allow from 116.203.164.16
ufw enable

If you have a T.Lion – T.Brother configuration, consider setting the following additional rules on both the T.Lion and T.Brother hosts:

ufw default deny incoming
ufw default allow outgoing
ufw allow ssh
ufw allow 22
ufw allow 65000:65020/tcp
ufw allow 4000/tcp
ufw allow 4321/tcp
ufw allow 4567/udp
ufw allow 4567/tcp
ufw allow 4444/tcp
ufw allow 13000/tcp
ufw allow 27017/tcp
ufw allow 65000:65020/udp
ufw allow 8082/tcp
ufw allow from 116.203.164.16
ufw enable

On the Arbitrator host:

ufw default deny incoming
ufw default allow outgoing
ufw allow ssh
ufw allow 22
ufw allow 13000/tcp
ufw enable