ZyXEL Communications G-2000 Plus V2, Руководство пользователя

Страница: 125 / 440

ZyXEL G-2000 Plus v2 User’s Guide
Chapter 8 Single User Account (SUA) / Network Address Translation (NAT) 125
8.6 Trigger Port Forwarding
Some services use a dedicated range of ports on the client side and a dedicated range of ports
on the server side. With regular port forwarding you set a forwarding port in NAT to forward a
service (coming in from the server on the WAN) to the IP address of a computer on the client
side (LAN). The problem is that port forwarding only forwards a service to a single LAN IP
address. In order to use the same service on a different LAN computer, you have to manually
replace the LAN computer's IP address in the forwarding port with another LAN computer's IP
address,
Trigger port forwarding solves this problem by allowing computers on the LAN to
dynamically take turns using the service. The ZyXEL device records the IP address of a LAN
computer that sends traffic to the WAN to request a service with a specific port number and
protocol (a "trigger" port). When the ZyXEL device's WAN port receives a response with a
specific port number and protocol ("incoming" port), the ZyXEL device forwards the traffic to
the LAN IP address of the computer that sent the request. After that computer’s connection for
that service closes, another computer on the LAN can use the service in the same manner. This
way you do not need to configure a new IP address each time you want a different LAN
computer to use the application.
Table 43 Address Mapping Edit
LABEL DESCRIPTION
Type Choose the port mapping type from one of the following.
1.
One-to-One : One-to-one mode maps one local IP address to one global IP
address. Note that port numbers do not change for One-to-one NAT mapping
type.
2.
Many-to-One : Many-to-One mode maps multiple local IP addresses to one
global IP address. This is equivalent to SUA (i.e., PAT, port address translation),
ZyXEL device's Single User Account feature.
3.
Many-to-Many Overload : Many-to-Many Overload mode maps multiple local
IP addresses to shared global IP addresses.
4.
Many One-to-One : Many One-to-one mode maps each local IP address to
unique global IP addresses.
5.
Server : This type allows you to specify inside servers of different services
behind the NAT to be accessible to the outside world.
Local Start IP This is the starting Inside Local IP Address (ILA). Local IP addresses are N/A for
Server port mapping.
Local End IP This is the end Inside Local IP Address (ILA). If your rule is for all local IP
addresses, then enter 0.0.0.0 as the Local Start IP address and
255.255.255.255 as the Local End IP address.
This field is N/A for One-to-One and Server mapping types.
Global Start IP This is the starting Inside Global IP Address (IGA). Enter 0.0.0.0 here if you have
a dynamic IP address from your ISP.
Global End IP This is the ending Inside Global IP Address (IGA). This field is N/A for One-to-
One , Many-to-One and Server mapping types.
Apply Click Apply to save your changes back to the ZyXEL device.
Cancel Click Cancel to return to the previous screen and not save your changes.