ZyXEL Communications P-2608HWL-Dx Series User Manual

P-2608HWL-Dx Series User’s Guide

Chapter 10 Network Address Translation (NAT) Screens

149

The following table describes the fields in this screen. 

Some NAT routers may include a SIP Application Layer Gateway (ALG). A SIP ALG allows 
SIP calls to pass through NAT by examining and translating IP addresses embedded in the 
data stream. When the ZyXEL Device registers with the SIP register server, the SIP ALG 
translates the ZyXEL Device’s private IP address inside the SIP data stream to a public IP 
address. You do not need to use STUN or an outbound proxy if your ZyXEL Device is behind 
a SIP ALG.

Use this screen to enable and disable the SIP (VoIP) ALG in the ZyXEL Device. To access 
this screen, click Network > NAT > ALG.

Table 51   Edit Address Mapping Rule 

Type

Choose the port mapping type from one of the following. 
•

One-to-One: One-to-One mode maps one local IP address to one global IP 

address. Note that port numbers do not change for One-to-one NAT mapping 

type.

•

Many-to-One: Many-to-One mode maps multiple local IP addresses to one 

global IP address. This is equivalent to SUA (i.e., PAT, port address translation), 

ZyXEL's Single User Account feature that previous ZyXEL routers supported 

only. 

•

Many-to-Many Overload: Many-to-Many Overload mode maps multiple local IP 

addresses to shared global IP addresses. 

•

Many-to-Many No Overload: Many-to-Many No Overload mode maps each 

local IP address to unique global IP addresses. 

•

Server: This type allows you to specify inside servers of different services behind 

the NAT to be accessible to the outside world.

Local Start IP

This is the starting local IP address (ILA). Local IP addresses are N/A for Server port 

mapping.

Local End IP

This is the end local IP address (ILA). If your rule is for all local IP addresses, then 

enter 0.0.0.0 as the Local Start IP address and 255.255.255.255 as the Local End 

IP address. 
This field is N/A for One-to-One and Server mapping types.

Global Start IP

This is the starting global IP address (IGA). Enter 0.0.0.0 here if you have a dynamic 

IP address from your ISP. 

Global End IP

This is the ending global IP address (IGA). This field is N/A for One-to-One, Many-

to-One and Server mapping types.

Server Mapping 

Set

Only available when Type is set to Server. 
Select a number from the drop-down menu to choose a server mapping set.

Edit Details

Click this link to go to the Port Forwarding screen to edit a server mapping set that 

you have selected in the Server Mapping Set field.

Back

Click Back to return to the previous screen.

Apply

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

Cancel

Click Cancel to begin configuring this screen afresh.