ZyXEL Communications Prestige 642R Series - Manual (Page 114)

Prestige 642R Series ADSL Router
8-18 Filter Configuration
Figure 8-14 Example Filter - Menu 21.3.1
When you press [ENTER] to confirm, you will see the following screen. Note that there is only one filter
rule in this set.
Menu 21.3.1 - 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 #=
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 Space Bar to Toggle.
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.
The port number for the telnet
service (TCP protocol) is 23.
See RFC 1060 for port numbers
of well-known services.
Select Equal
here as we are
looking for
packets going to
port 23 only.
There are no
more rules to
check.
Select Drop here so that
the packet will be
dropped if its destination
is the telnet port.
Select Forward here so that
the packet will be forwarded
if its destination is not the
telnet port.