Chapter 21 Network Address Translation (NAT)
ZyWALL 5/35/70 Series User’s Guide
441
You may enter a single port number or a range of port numbers to be forwarded, and the local
IP address of the desired server. The port number identifies a service; for example, web
service is on port 80 and FTP on port 21. In some cases, such as for unknown services or
where one server can support more than one service (for example both FTP and web service),
it might be better to specify a range of port numbers. You can allocate a server IP address that
corresponds to a port or a range of ports.
Many residential broadband ISP accounts do not allow you to run any server processes (such
as a Web or FTP server) from your location. Your ISP may periodically check for servers and
may suspend your account if it discovers any active services at your location. If you are
unsure, refer to your ISP.
21.5.1 Default Server IP Address
In addition to the servers for specified services, NAT supports a default server IP address. A
default server receives packets from ports that are not specified in this screen.
"
If you do not assign a
Default Server
IP address, the ZyWALL discards all
packets received for ports that are not specified here or in the remote
management setup.
21.5.2 Port Forwarding: Services and Port Numbers
The ZyWALL provides the additional safety of the DMZ ports for connecting your publicly
accessible servers. This makes the LAN more secure by physically separating it from your
public servers.
Use the
Port Forwarding
screen to forward incoming service requests to the server(s) on your
local network.
The most often used port numbers are shown in
Appendix F on page 813
. Please refer to RFC
1700 for further information about port numbers.
21.5.3 Configuring Servers Behind Port Forwarding (Example)
Let's say you want to assign ports 21-25 to one FTP, Telnet and SMTP server (
A
in the
example), port 80 to another (
B
in the example) and assign a default server IP address of
192.168.1.35 to a third (
C
in the example). You assign the LAN IP addresses and the ISP
assigns the WAN IP address. The NAT network appears as a single host on the Internet.
Summary of Contents for ZyWALL 35 Series
Page 2: ......
Page 8: ...Safety Warnings ZyWALL 5 35 70 Series User s Guide 8 ...
Page 52: ...List of Tables ZyWALL 5 35 70 Series User s Guide 52 ...
Page 54: ...54 ...
Page 60: ...Chapter 1 Getting to Know Your ZyWALL ZyWALL 5 35 70 Series User s Guide 60 ...
Page 86: ...Chapter 2 Introducing the Web Configurator ZyWALL 5 35 70 Series User s Guide 86 ...
Page 140: ...Chapter 4 Tutorials ZyWALL 5 35 70 Series User s Guide 140 ...
Page 146: ...Chapter 5 Registration ZyWALL 5 35 70 Series User s Guide 146 ...
Page 148: ...148 ...
Page 160: ...Chapter 6 LAN Screens ZyWALL 5 35 70 Series User s Guide 160 ...
Page 173: ...Chapter 8 WAN Screens ZyWALL 5 35 70 Series User s Guide 173 Figure 93 NETWORK WAN General ...
Page 202: ...Chapter 8 WAN Screens ZyWALL 5 35 70 Series User s Guide 202 ...
Page 212: ...Chapter 9 DMZ Screens ZyWALL 5 35 70 Series User s Guide 212 ...
Page 242: ...242 ...
Page 274: ...Chapter 11 Firewall ZyWALL 5 35 70 Series User s Guide 274 ...
Page 294: ...Chapter 13 Configuring IDP ZyWALL 5 35 70 Series User s Guide 294 ...
Page 320: ...Chapter 15 Anti Spam ZyWALL 5 35 70 Series User s Guide 320 ...
Page 342: ...Chapter 16 Content Filtering Screens ZyWALL 5 35 70 Series User s Guide 342 ...
Page 350: ...Chapter 17 Content Filtering Reports ZyWALL 5 35 70 Series User s Guide 350 ...
Page 424: ...Chapter 19 Certificates ZyWALL 5 35 70 Series User s Guide 424 ...
Page 430: ...430 ...
Page 448: ...Chapter 21 Network Address Translation NAT ZyWALL 5 35 70 Series User s Guide 448 ...
Page 474: ...Chapter 24 Bandwidth Management ZyWALL 5 35 70 Series User s Guide 474 ...
Page 514: ...Chapter 26 Remote Management ZyWALL 5 35 70 Series User s Guide 514 ...
Page 533: ...533 PART V Reports Logs and Maintenance Reports 535 Logs Screens 547 Maintenance 575 ...
Page 534: ...534 ...
Page 551: ...Chapter 31 Logs Screens ZyWALL 5 35 70 Series User s Guide 551 Figure 334 LOGS Log Settings ...
Page 592: ...Chapter 32 Maintenance ZyWALL 5 35 70 Series User s Guide 592 ...
Page 594: ...594 Troubleshooting 751 Product Specifications 757 ...
Page 602: ...Chapter 33 Introducing the SMT ZyWALL 5 35 70 Series User s Guide 602 ...
Page 622: ...Chapter 35 WAN and Dial Backup Setup ZyWALL 5 35 70 Series User s Guide 622 ...
Page 628: ...Chapter 36 LAN Setup ZyWALL 5 35 70 Series User s Guide 628 ...
Page 634: ...Chapter 37 Internet Access ZyWALL 5 35 70 Series User s Guide 634 ...
Page 638: ...Chapter 38 DMZ Setup ZyWALL 5 35 70 Series User s Guide 638 ...
Page 642: ...Chapter 39 Route Setup ZyWALL 5 35 70 Series User s Guide 642 ...
Page 658: ...Chapter 41 Remote Node Setup ZyWALL 5 35 70 Series User s Guide 658 ...
Page 662: ...Chapter 42 IP Static Route Setup ZyWALL 5 35 70 Series User s Guide 662 ...
Page 700: ...Chapter 45 Filter Configuration ZyWALL 5 35 70 Series User s Guide 700 ...
Page 738: ...Chapter 50 Remote Management ZyWALL 5 35 70 Series User s Guide 738 ...
Page 746: ...Chapter 51 IP Policy Routing ZyWALL 5 35 70 Series User s Guide 746 ...
Page 766: ...766 ...
Page 770: ...Appendix A Hardware Installation ZyWALL 5 35 70 Series User s Guide 770 ...
Page 780: ...Appendix C Removing and Installing a Fuse ZyWALL 5 35 70 Series User s Guide 780 ...
Page 802: ...Appendix D Setting up Your Computer s IP Address ZyWALL 5 35 70 Series User s Guide 802 ...
Page 816: ...Appendix F Common Services ZyWALL 5 35 70 Series User s Guide 816 ...
Page 852: ...Appendix J Importing Certificates ZyWALL 5 35 70 Series User s Guide 852 ...
Page 856: ...Appendix K Legal Information ZyWALL 5 35 70 Series User s Guide 856 ...
Page 862: ...Appendix L Customer Support ZyWALL 5 35 70 Series User s Guide 862 ...