Chapter 36 Network Address Translation (NAT)
ZyWALL 2 Plus User’s Guide
537
Figure 363
Example 4: Menu 15.1.1: Address Mapping Rules
36.5 Trigger Port Forwarding
Some services use a dedicated range of ports on the client side and a dedicated range of ports
on the server side. With regular port forwarding you set a forwarding port in NAT to forward a
service (coming in from the server on the WAN) to the IP address of a computer on the client
side (LAN). The problem is that port forwarding only forwards a service to a single LAN IP
address. In order to use the same service on a different LAN computer, you have to manually
replace the LAN computer's IP address in the forwarding port with another LAN computer's IP
address.
Trigger port forwarding solves this problem by allowing computers on the LAN to
dynamically take turns using the service. The ZyWALL records the IP address of a LAN
computer that sends traffic to the WAN to request a service with a specific port number and
protocol (a "trigger" port). When the ZyWALL's WAN port receives a response with a specific
port number and protocol ("incoming" port), the ZyWALL forwards the traffic to the LAN IP
address of the computer that sent the request. After that computer’s connection for that service
closes, another computer on the LAN can use the service in the same manner. This way you do
not need to configure a new IP address each time you want a different LAN computer to use
the application.
36.5.1 Two Points To Remember About Trigger Ports
1
Trigger events only happen on data that is going coming from inside the ZyWALL and
going to the outside.
2
If an application needs a continuous data stream, that port (range) will be tied up so that
another computer on the LAN can’t trigger it.
Menu 15.1.1 - Address Mapping Rules
Set Name= Example4
Idx Local Start IP Local End IP Global Start IP Global End IP Type
--- --------------- --------------- --------------- --------------- ---
1. 192.168.1.10 192.168.1.12 10.132.50.1 10.132.50.3 M-1-1
2.
3.
4.
5.
6.
7.
8.
9.
10.
Action= Edit Select Rule=
Press ENTER to Confirm or ESC to Cancel:
Summary of Contents for ADSL 2+ Security Gateway
Page 2: ......
Page 25: ...Table of Contents ZyWALL 2 Plus User s Guide 25 Index 679 ...
Page 26: ...Table of Contents ZyWALL 2 Plus User s Guide 26 ...
Page 46: ...46 ...
Page 88: ...Chapter 3 Wizard Setup ZyWALL 2 Plus User s Guide 88 ...
Page 132: ...132 ...
Page 144: ...Chapter 6 LAN Screens ZyWALL 2 Plus User s Guide 144 ...
Page 180: ...Chapter 9 DMZ Screens ZyWALL 2 Plus User s Guide 180 ...
Page 190: ...190 ...
Page 222: ...Chapter 11 Firewall ZyWALL 2 Plus User s Guide 222 ...
Page 252: ...Chapter 13 Content Filtering Reports ZyWALL 2 Plus User s Guide 252 ...
Page 328: ...Chapter 16 Authentication Server ZyWALL 2 Plus User s Guide 328 ...
Page 330: ...330 ...
Page 346: ...Chapter 17 Network Address Translation NAT ZyWALL 2 Plus User s Guide 346 ...
Page 350: ...Chapter 18 Static Route ZyWALL 2 Plus User s Guide 350 ...
Page 398: ...Chapter 21 Remote Management ZyWALL 2 Plus User s Guide 398 ...
Page 416: ...Chapter 24 ALG Screen ZyWALL 2 Plus User s Guide 416 ...
Page 417: ...417 PART V Logs and Maintenance Logs Screens 419 Maintenance 447 ...
Page 418: ...418 ...
Page 423: ...Chapter 25 Logs Screens ZyWALL 2 Plus User s Guide 423 Figure 274 LOGS Log Settings ...
Page 466: ...466 ...
Page 474: ...Chapter 27 Introducing the SMT ZyWALL 2 Plus User s Guide 474 ...
Page 496: ...Chapter 30 LAN Setup ZyWALL 2 Plus User s Guide 496 ...
Page 504: ...Chapter 32 DMZ Setup ZyWALL 2 Plus User s Guide 504 ...
Page 508: ...Chapter 33 Wireless Setup ZyWALL 2 Plus User s Guide 508 ...
Page 556: ...Chapter 38 Filter Configuration ZyWALL 2 Plus User s Guide 556 ...
Page 570: ...Chapter 40 System Information Diagnosis ZyWALL 2 Plus User s Guide 570 ...
Page 586: ...Chapter 41 Firmware and Configuration File Maintenance ZyWALL 2 Plus User s Guide 586 ...
Page 594: ...Chapter 42 System Maintenance Menus 8 to 10 ZyWALL 2 Plus User s Guide 594 ...
Page 598: ...Chapter 43 Remote Management ZyWALL 2 Plus User s Guide 598 ...
Page 604: ...604 ...
Page 612: ...Chapter 45 Troubleshooting ZyWALL 2 Plus User s Guide 612 ...
Page 620: ...620 ...
Page 644: ...Appendix B Pop up Windows JavaScripts and Java Permissions ZyWALL 2 Plus User s Guide 644 ...
Page 668: ...Appendix E Importing Certificates ZyWALL 2 Plus User s Guide 668 ...
Page 672: ...Appendix F Legal Information ZyWALL 2 Plus User s Guide 672 ...
Page 678: ...Appendix G Customer Support ZyWALL 2 Plus User s Guide 678 ...