Filter types and nat, 4 filter types and nat – ZyXEL Communications ZyXEL ZyAIR 100 User Manual
Page 419

ZyWALL 10~100 Series Internet Security Gateway
Filter Configuration
31-15
Figure 31-11 Example Filter Rules Summary: Menu 21.1.3
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 [SPACE BAR] to select Yes and press [ENTER].
Step 3. This brings you to menu 11.5. Apply a filter set (our example filter set 3) as shown in Figure
31-15.
Step 4. Press [ENTER] to confirm after you enter the set numbers and to leave menu 11.5.
31.4 Filter Types and NAT
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 NAT (Network
Menu 21.1.3 - Filter Rules Summary
# A Type Filter Rules M m n
- - ---- --------------------------------------------------------------- - - -
1 Y IP Pr=6, SA=0.0.0.0, DA=0.0.0.0, DP=23 N D F
2 N
3 N
4 N
5 N
6 N
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).
M = N means an action can be taken immediately.
The action is to drop the packet (m = D) if the
action is matched and to forward the packet
immediately (n = F) if the action is not matched no
matter whether there are more rules to be
checked (there aren’t in this example).