Hi

Big subject :-)

1) fixup protocol. Generally the pix looks at layer 3 (IP addresses) and layer 4 (port numbers). However for some applications it can look at the layer 7 information ie. it understands certain commands etc, used by the application. The applications it can do this for are defined by the fixup protocol lines.

2) failover - this is used when you have two firewalls in a pair. One is generally active and the other is in failover mode and will assume the active role if the primary firewall fails. Note that with v7.0 of the pix software you can run both in active mode if you want on a per context basis.

3) access-lists are used to control the traffic allowed through the firewall, either from inside to outside or outside to inside, or outside to DMZ etc...

By default traffic is allowed to flow from a higher security interface to a lower security interface without an access-list eg inside to outside.

Attached is a link to the pix firewall configuration docs.

http://www.cisco.com/en/US/products/sw/secursw/ps2120/products_installation_and_configuration_guides_list.html

HTH

Jon