ZyXEL p-2802h-i1 Guia Do Utilizador

Chapter 9 Network Address Translation (NAT) Screens

P-2802H(W)(L)-I Series User’s Guide

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.

Figure 70   Network > NAT > ALG

Each field is described in the following table.

Table 45   Network > NAT > ALG

Enable SIP ALG

Select this to make sure SIP (VoIP) works correctly with port-forwarding and 

address-mapping rules.

Apply

Click this to save your changes and to apply them to the ZyXEL Device.

Reset

Click this to return to previously saved configuration.