NISTGuidelines on Firewalls and Firewall Policy

Firewallsaredevicesorprogramsthatcontroltheflowofnetworktrafficbetweennetworksorhostsemployingdifferingsecuritypostures.Thispublicationprovidesanoverviewofseveraltypesoffirewalltechnologiesanddiscussestheirsecuritycapabilitiesandtheirrelativeadvantagesanddisadvantagesindetail.Italsomakes