Chapter 8 Network Address Translation (NAT)

8.6 The ALG 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. The SIP ALG translates the P-870HN-51D’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 you enable the SIP ALG.

Use this screen to enable or disable the SIP (VoIP) ALG in the P-870HN-51D. To access this screen, click NAT > ALG.

Figure 68 NAT > ALG

Each field is described in the following table.

Table 42 NAT > ALG

LABEL

DESCRIPTION

Active SIP ALG

Select this check box to allow SIP sessions to pass through the P-

 

870HN-51D. SIP is a signaling protocol used in VoIP (Voice over IP), the

 

sending of voice signals over Internet Protocol.

 

 

Apply

Click Apply to save your customized settings.

 

 

8.7 Technical Reference

The following section contains additional technical information about the P-870HN- 51D features described in this chapter.

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P-870HN-51D User’s Guide