When Do I Need Multi-Nat; What Ip/Port Mapping Does Multi-Nat Support - ZyXEL Communications P-2812HNU-51c Support Notes

When do I need Multi-NAT?

a. Make local server accessible from outside Internet
When NAT is enabled the local computers are not accessible from outside. You can
use Multi-NAT to make an internal server accessible from outside.
a. Support Non-NAT Friendly Applications
Some servers providing Internet applications such as some mIRC servers do not allow
users to login using the same IP address. Thus, users on the same network can not
login to the same server simultaneously. In this case it is better to use Many-to-Many
No Overload or One-to-One NAT mapping types, thus each user login to the server
using a unique global IP address.

What IP/Port mapping does Multi-NAT support?

NAT supports five types of IP/port mapping. They are: One to One, Many to One,
Many to Many Overload, Many to Many No Overload and Server. The details of the
mapping between ILA and IGA are described as below. Here we define the local IP
addresses as the Internal Local Addresses (ILA) and the global IP addresses as the
Inside Global Address (IGA),
1. One to One
In One-to-One mode, the device maps one ILA to one IGA.
2. Many to One
In Many-to-One mode, the device maps multiple ILA to one IGA. This is equivalent to
SUA (i.e., PAT, port address translation), ZyXEL's Single User Account feature that
previous ZyNOS routers supported (the SUA only option in today's routers).
3. Many to Many Overload
In Many-to-Many Overload mode, the device maps the multiple ILA to shared IGA.
4. Many to Many No Overload
In Many-to-Many No Overload mode, the device maps each ILA to unique IGA.
5. Server
All contents copyright (c) 2009 ZyXEL Communications Corporation.
P-2812HNU-51C Support Notes