Chapter 8 Network Address Translation (NAT)
P-870HN-51D User’s Guide
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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.
8.7 Technical Reference
The following section contains additional technical information about the P-870HN-
51D features described in this chapter.
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.
