ZyXEL Communications p-2612HNU-FX User Manual

Chapter 8 Network Address Translation (NAT)

P-2612HNU-Fx User’s Guide

This section provides some technical background information about the topics 
covered in this chapter.

Inside/outside denotes where a host is located relative to the ZyXEL Device, for 
example, the computers of your subscribers are the inside hosts, while the web 
servers on the Internet are the outside hosts. 

Global/local denotes the IP address of a host in a packet as the packet traverses a 
router, for example, the local address refers to the IP address of a host when the 
packet is in the local network, while the global address refers to the IP address of 
the host when the same packet is traveling in the WAN side. 

Note that inside/outside refers to the location of a host, while global/local refers to 
the IP address of a host used in a packet. Thus, an inside local address (ILA) is the 
IP address of an inside host in a packet when the packet is still in the local 
network, while an inside global address (IGA) is the IP address of the same inside 

External End 
Port 

Enter the last port of the original destination port range. 

To forward only one port, enter the port number in the External Start 
Port field above and then enter it again in this field. 

To forward a series of ports, enter the last port number in a series that 
begins with the port number in the External Start Port field above.

Internal Start 
Port

This shows the port number to which you want the ZyXEL Device to 
translate the incoming port. For a range of ports, enter the first number 
of the range to which you want the incoming ports translated.

Internal End 
Port 

This shows the last port of the translated port range.

Protocol Type

Select the protocol supported by this virtual server. Choices are TCP, 
UDP, or TCP/UDP.

Apply

Click this to save your changes back to the ZyXEL Device.

Cancel

Click this to begin configuring this screen afresh.

Table 35   Port Forwarding Edit (continued)