Figure 30-9 Example Filter: Menu 21.1.3.1 - ZyXEL Communications Internet Security Gateway ZyWALL 2 Series User Manual

ZyWALL 2 Series User's Guide
Filter #: 3,1
Filter Type= TCP/IP Filter Rule
Active= Yes
IP Protocol= 6
Destination: IP Addr= 0.0.0.0
TCP Estab= No
More= No
Action Matched= Drop
Action Not Matched= Forward
Press ENTER to Confirm or ESC to Cancel:
Press Space Bar to Toggle.
There are no
more rules to
check.
Select Drop here so that the
packet will be dropped if its
destination is the telnet port.
When you press [ENTER] to confirm, you will see the following screen. Note that there is only one filter rule
in this set.
30-14
Menu 21.1.3.1 - TCP/IP Filter Rule
IP Source Route= No
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
Log= None

Figure 30-9 Example Filter: Menu 21.1.3.1

Select Equal here
as you are looking
for packets going
to port 23 only.
Select Forward here so that the
packet will be forwarded if its
destination is not the telnet port.
Press [SPACE BAR] and then
[ENTER] 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.
The port number for the telnet
service (TCP protocol) is 23. See
RFC 1060 for port numbers of well-
known services.
Filter Configuration