ZyXEL Communications ADSL2+4 User Manual

Chapter 8 Network Address Translation (NAT)

P-660H-T1v3s User’s Guide

The following figure illustrates a possible NAT application, where three inside LANs 
(logical LANs using IP alias) behind the P-660H-T1v3s can communicate with three 
distinct WAN networks.

Figure 44   NAT Application With IP Alias

NAT supports five types of IP/port mapping. They are:

• One to One: In One-to-One mode, the P-660H-T1v3s maps one local IP 

address to one global IP address.

• Many to One: In Many-to-One mode, the P-660H-T1v3s 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 P-660H-T1v3s 

maps the multiple local IP addresses to shared global IP addresses.

• Many-to-Many No Overload: In Many-to-Many No Overload mode, the P-

660H-T1v3s 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.