User`s guide
Chapter 9 Network Address Translation (NAT)
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The following table describes the fields in this screen.
9.5 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.
When the Device registers with the SIP register server, the SIP ALG translates the 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 you enable this Device’s SIP ALG.
Use the ALG screen to enable and disable the SIP (VoIP) ALG in the Device. To access this screen,
click Network Setting > NAT > ALG.
Figure 89 Network Setting > NAT > ALG
The following table describes the fields in this screen.
9.6 NAT Technical Reference
This chapter contains more information regarding NAT.
Table 45 Network Setting > NAT > DMZ
LABEL DESCRIPTION
WAN Interface Select a WAN PVC connection (PVC0~PVC7) from which you want to forward the traffic
to the specified default server.
Default Server
Address
Enter the IP address of the default server which receives packets from ports that are not
specified in the NAT > Port Forwarding screen.
Note: If you do not assign a Default Server Address, the Device discards all packets
received for ports that are not specified in the NAT Port Forwarding screen.
Apply Click Apply to save your changes.
Cancel Click Cancel to restore your previously saved settings.
Table 46 Network Setting > NAT > ALG
LABEL DESCRIPTION
ALG Select Enable to make sure SIP (VoIP) works correctly with NAT.
Apply Click Apply to save your changes.
Cancel Click Cancel to restore your previously saved settings.