Filter
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ZyWALL 50 Internet Security Gateway
Filter Configuration 15-15
Step 3. Enter a descriptive name or comment in the Edit Comments field and press [ENTER].
Step 4. Press [ENTER] at the message [Press ENTER to confirm] to open Menu 21.1.1 - Filter
Rules Summary.
Step 5. Enter 1 to configure the first filter rule (the only filter rule of this set). Make the entries in this
menu as shown in the following figure.
Figure 15-12 Example Filter — Menu 21.1.3.1
Menu 21.1.3.1 - TCP/IP Filter Rule
Filter #: 3,1
Filter Type= TCP/IP Filter Rule
Active= Yes
IP Protocol= 6 IP Source Route= No
Destination: IP Addr= 0.0.0.0
IP Mask= 0.0.0.0
Port #= 23
Port # Comp= Equal
Source: IP Addr= 0.0.0.0
IP Mask= 0.0.0.0
Port #= 0
Port # Comp= None
TCP Estab= No
More= No Log= None
Action Matched= Drop
Action Not Matched= Forward
Press ENTER to Confirm or ESC to Cancel:
Press S
p
ace Bar to To
gg
le.
Press [SPACE BAR] to choose this filter
rule type. The first filter rule type
determines all subsequent filter types
within a set.
Select Yes to make the rule active.
6 is the TCP protocol.
Select Equal here as you are looking for
packets going to port 23 only.
There are no more rules to
check.
Select Forward here so that the packet
will be forwarded if its destination is not
the telnet port.
The port number for the telnet service (TCP
protocol) is 23. See RFC 1060 for port numbers
of well-known services.
Select Drop here so that the packet
will be dropped if its destination is
the telnet port.