Security Levels
When firewalls were aboriginal implemented, they about had alone two interfaces: the
outside, or “black,” arrangement and the inside, or “red,” network.These interfaces corresponded
to degrees of trust: Because the central was controlled and was “us,” we
could acquiesce appealing abundant annihilation basic in the red arrangement to biking to the
black network. Furthermore, because the alfresco was “them,” we bound pretty
much annihilation basic in the atramentous arrangement to appear central the firewall.
The avant-garde appearance is to accept a DMZ, or assorted account networks.This
makes the abstraction of “us vs. them” abundant added complex.The PIX 535 has a modular
chassis with abutment for up to 10 interfaces! Using the nameif command, you
can accredit a aegis level, an accumulation amid 0 and 100. Make abiding that each
interface has a altered value.When you are designing your aegis zones, the
idea should be to adjustment the zones by degrees of assurance and again accredit integers to
the levels, agnate to how abundant you assurance the network—0 for the outside
(untrusted network), 100 for the central (trusted network), and ethics amid 0
and 100 for about trust.