Comparing firewalls (softwares)

Lexic

IP Firewall

Shows "best" firewalls that filters at low level (IP protocol - layer 2) from those that only filters upper layers (generally TCP layer).

Non IP Firewall

Tell if the firewall is "able" to forbid non IP protocols (such as NetBeui, IPX) which gives better security.

NAT (Network Address Translation)

Usefull when having local network area using a one-entry internet acces point (such as Cable or DSL), the address translation allows your other PC's of your LAN to simlply acces Internet.

DHCP

Some softwares allows DHCP ports and its dynamic control onto your LAN (usefull only if you have a LAN).

Proxy

The proxy system allows to give Internet access to your LAN,it's a different process from NAT.

VPN (Virtual Private Network)

Fonctionnality allowing to create a private network (virtual) with two (or more) different area using Internet. This protocol use secure functions to crypt the exchanged datas between the areas.

DNS

Shows if the software provides a DNS replication on your LAN.

URL Filtering

Usefull mainly for parental guidance and for corporations wishing to restrict access to the Web.

Ext

With Linux, it's not an external software functionnality but a kernel configuration.