Filter Types And Sua - ZyXEL Communications Prestige 314 User Manual

Menu 21.3 - Filter Rules Summary
# A Type
- - ---- --------------------------------------------------------------- - - -
1 Y IP Pr=6, SA=0.0.0.0, DA=0.0.0.0, DP=23
2 N
3 N
4 N
5 N
6 N
Enter Filter Rule Number (1-6) to Configure: 1
This shows you that you have
configured and activated (A =
Y) a TCP/IP filter rule (Type =
IP, Pr = 6) for destination
telnet ports (DP = 23).
Figure 7-12
Configure the next filter rules in this set in the same way. After you've created the filter set, you must apply
it.
Step 1. Enter 11 from the main menu to go to Menu 11.
Step 2. Go to the Edit Filter Sets field, press the [SPACE BAR] to toggle Yes to No and press
[ENTER].
Step 3.
This brings you to Menu 11.5. Apply the TELNET_FTP_Web_WAN filter set (filter set 3) as
shown in Figure 7-15.
Step 4. Press [ENTER] to confirm after you enter the set numbers and to leave Menu 11.5.
7.4

Filter Types and SUA

There are two classes of filter rules, Generic Filter (Device) rules and Protocol Filter (TCP/IP) rules.
Generic Filter rules act on the raw data from/to LAN and WAN. Protocol Filter rules act on the IP packets.
Generic and TCP/IP filter rules are discussed in more detail in the next section. When SUA (Single User
Account) is enabled, the inside IP address and port number are replaced on a connection-by-connection basis,
which makes it impossible to know the exact address and port on the wire. Therefore, the Prestige applies
the protocol filters to the "native" IP address and port number before SUA for outgoing packets and after
Filter Configuration
P314 Broadband Sharing Gateway with 4-Port Switch
Filter Rules
M = N means an action can be taken
immediately, i.e., we don't need more rules
to block telnet. The action is to drop the
packet if the action is matched (m = D) and
the next rule is checked (n = N) if the
action is not matched.
Example Filter Rules Summary – Menu 21.3
M m n
N D N
7-15