ufw - Ufw stands for Uncomplicated Firewall, and is program for managing a netfilter firewall.
Symantec Email Security.cloud - Symantec Email Security.cloud provides always-on, inbound and outbound email security against malware, targeted attacks, and advanced threats
TinyWall - Lightweight and non-intrusive firewall
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
Gufw - Gufw is an easy, intuitive way to manage your Linux firewall.
SonicWall - SonicWall security solutions protects your network, systems, users and data from cyber threats.