ZyXEL Communications P-661H Series, User Manual, Page: 135 / 383

P-661H/HW Series User’s Guide
Chapter 7 Network Address Translation (NAT) Screens 135
7.1.4 NAT Application
The following figure illustrates a possible NAT application, where three inside LANs (logical
LANs using IP Alias) behind the ZyXEL Device can communicate with three distinct WAN
networks. More examples follow at the end of this chapter.
Figure 71 NAT Application With IP Alias
7.1.5 NAT Mapping Types
NAT supports five types of IP/port mapping. They are:
• One to One : In One-to-One mode, the ZyXEL Device maps one local IP address to one
global IP address.
• Many to One : In Many-to-One mode, the ZyXEL Device maps multiple local IP
addresses to one global IP address. This is equivalent to SUA (for instance, PAT, port
address translation), ZyXEL’s Single User Account feature that previous ZyXEL routers
supported (the
SUA Only option in today’s routers).
• Many to Many Overload : In Many-to-Many Overload mode, the ZyXEL Device maps
the multiple local IP addresses to shared global IP addresses.
• Many-to-Many No Overload : In Many-to-Many No Overload mode, the ZyXEL Device
maps each local IP address to a unique global IP address.
• Server : This type allows you to specify inside servers of different services behind the
NAT to be accessible to the outside world.