Filter
Top Products
92Chapter 12 - Filters and Rules
Cyclades-PR1000
Interior Router
If an interior router exists in the network, the administrator may decide to use a
Default Scope
of
Permit
. In this
case, all undesired traffic must be excluded by a rule in the rule list. In Figure 12.5, a conceptual equivalent of the
interface is shown.
All packets except those which fall into the holes in the ball will be allowed entry in to or out of the network.
Stop
Forged Packets
W
o
r
l
d
o
f
P
o
s
si
b
l
e
P
a
c
k
e
t
s
Don’t Allow
Access to News
PERMIT
PERMIT
PERMIT
Stop Telnets
From the Outside
(Except Bastion Host)
FIGURE 12.5 PERMIT DEFAULT SCOPE