Chapter 10 Network Address Translation (NAT) Screens

10.6.2 SIP ALG

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 85 Network > NAT > ALG

Each field is described in the following table.

Table 50 Network > NAT > ALG

LABEL

DESCRIPTION

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.

 

 

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P-2602H(W)(L)-DxA User’s Guide