Distributions:Secure

• NetSecL
  
  NetSecL (previously known as ISlack) is a security-focused Linux distribution. It includes Grsecurity by default. Most of the numerous security-related software is suited for penetration testing of your network. There are also security tools for testing your local security and IDSs for monitoring. The configuration of NetSecL is hardened by default: (listening for connection) services are turned off, and incoming ports are closed.

Software:Networking:Firewalls

• netsecl-firewall
  
  NetSecL-Firewall is an iptables script that protects against stealth scans, port scans, OS fingerprints, and other types of scanning.