Trust Radius – Web Content Filtering Solutions

NIST SP 800-53: SC-7 Boundary Protection

Department of Homeland Security – Web Content Filtering and Protections

Colorado Department of Education – Network Firewall Implementation Policy

Texas Wesleyan University – Sample Firewall Policy

Microsoft – Firewalls

SANS Whitepaper – Achieving Defense-in-Depth with Internal Firewalls

Microsoft – Perimeter Firewall Design

NIST SP 800-41 Guidelines on Firewalls and Firewall Policy

SANS Institute – Firewall Checklist