ZyXEL Communications P-660HN-F1, User Manual

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Chapter 11 Network Address Translation (NAT)
ADSL Series User’s Guide
179
Figure 87
Network Setting > NAT > Sessions
The following table describes the fields in this screen.
11.4 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 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 Setting > NAT > ALG.
Figure 88
Network > NAT > ALG
The following table describes the fields in this screen.
Table 49
Network Setting > NAT > Sessions
LABEL DESCRIPTION
MAX NAT Sessions Use this field to set a common limit to the number of concurrent NAT sessions each
client computer can have.
If only a few clients use peer to peer applications, you can raise this number to improve
their performance. With heavy peer to peer application use, lower this number to
ensure no single client uses too many of the available NAT sessions.
Apply Click Apply to save your changes.
Cancel Click Cancel to restore your previously saved settings.
Table 50
Network > NAT > ALG
LABEL DESCRIPTION
ALG Select enable to make sure SIP (VoIP) works correctly with port-forwarding and
address-mapping rules.
Apply Click this to save your changes.