Zoom Gateway/Router Zoom V3 - Manual (Page 50)

50 Zoom V3 User’s Guide
4
Using the V3’s Advanced
Firewall
This chapter describes the V3’s advanced firewall and the types
of protection it offers. If you are like most users, you probably
will not need to modify your firewall settings. If, however, you
are an administrator or an expert user who wants to customize
the firewall to protect a network against specific threats, you
should refer to this chapter.
You can think of the firewall as playing a role like that of a guard at
the gate of an ancient walled city. The guard has a great scroll,
which lists allowed and proscribed traffic. In one possible set of
rules, visitors may enter only if they show an invitation from a
citizen of the city. Children may not leave the city. The guard may
allow entry of carts of flour, but only for delivery to the bakery.
Any messenger who doesn’t know the password to the city is
thrown in the moat, and can’t pass through the gate.
You may set the policies of your firewall, which is like writing the
rules on the great scroll in the example. The firewall will then
follow the rules, acting like the guard. Instead of controlling entry
and exit of goods and people, you control entry and exit of
particular types of IP packets. In general, you will want to do this
to prevent unwanted packets from entering your network (this is
the purpose of the wall in the first place).