Firewall types

Firewalls primarily function using at least one of three methods: packet filtering, Network Address Translation (NAT), and proxy services. Crystal Enterprise works with these firewall types. Packet filtering rejects TCP/IP packets from unauthorized hosts and rejects connection attempts to unauthorized services. NAT translates the IP addresses of internal hosts to hide them from outside monitoring. NAT is also called IP masquerading. Proxy services make high-level application connections on behalf of internal hosts to completely break the network layer connection between internal and external hosts.

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• Packet filtering
• Network Address Translation
• SOCKS proxy servers