Filter
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129
Cyclades-PR4000
Chapter 14 - Filters and Rules
Filter_list Name exterior_out
Rule 0
Status Enabled
Scope Permit
Protocol TCP
Source IP Operator Equal
Source IP start 192.168.0.3
Source IP Mask 255.255.255.255
Destination IP Operator None
Source Port Operator Equal
Source Port Start SMTP
Destination Port Operator Greater than
Destination Port Start 1023
TCP connections allowed N
Account Process allowed N
FIGURE 12.4 OUTPUT FOR IP FILTERING EXAMPLE
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.