ZyXEL Communications P-870HW-I Series, User Manual

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P-870HW-I1 User’s Guide
Appendix D NAT 383
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 265 NAT Application With IP Alias
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 (i.e., PAT, port address
translation), ZyXEL’s Single User Account feature (the SUA Only option).
• 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 One-to-One : In Many-One-to-One 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.