Port Forwarding; Table 56 Nat General - ZyXEL Communications P-660HW-Tx v3 User Manual

The following table describes the labels in this screen.

Table 56 NAT General

LABEL
Active Network
Address
Translation (NAT)
SUA Only
Full Feature
Max NAT/Firewall
Session Per User
Enable SIP ALG
Apply
Cancel

10.4 Port Forwarding

A port forwarding set is a list of inside (behind NAT on the LAN) servers, for example, web or
FTP, that you can make visible to the outside world even though NAT makes your whole
inside network appear as a single computer to the outside world.
You may enter a single port number or a range of port numbers to be forwarded, and the local
IP address of the desired server. The port number identifies a service; for example, web
service is on port 80 and FTP on port 21. In some cases, such as for unknown services or
where one server can support more than one service (for example both FTP and web service),
it might be better to specify a range of port numbers. You can allocate a server IP address that
corresponds to a port or a range of ports.
Many residential broadband ISP accounts do not allow you to run any server processes (such
as a Web or FTP server) from your location. Your ISP may periodically check for servers and
may suspend your account if it discovers any active services at your location. If you are
unsure, refer to your ISP.
P-660HW-Tx v3 User's Guide
DESCRIPTION
Select this check box to enable NAT.
Select this radio button if you have just one public WAN IP address for your
ZyXEL Device.
Select this radio button if you have multiple public WAN IP addresses for your
ZyXEL Device.
When computers use peer to peer applications, such as file sharing applications,
they need to establish NAT sessions. If you do not limit the number of NAT
sessions a single client can establish, this can result in all of the available NAT
sessions being used. In this case, no additional NAT sessions can be
established, and users may not be able to access the Internet.
Each NAT session establishes a corresponding firewall session. Use this field to
limit the number of NAT/firewall sessions each client computer can establish
through the ZyXEL Device.
If your network has a small number of clients using peer to peer applications, you
can raise this number to ensure that their performance is not degraded by the
number of NAT sessions they can establish. If your network has a large number
of users using peer to peer applications, you can lower this number to ensure no
single client is using all of the available NAT sessions.
Select this to make sure SIP (VoIP) works correctly with port-forwarding and
address-mapping rules.
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.
Click Apply to save your changes to the ZyXEL Device.
Click Cancel to reload the previous configuration for this screen.
Chapter 10 Network Address Translation (NAT)
151