ZyXEL p-660hwp Manual Do Utilizador

Chapter 9 Network Address Translation (NAT)

P-660HWP-Dx User’s Guide

The following table summarizes these types.

SUA (Single User Account) is a ZyNOS implementation of a subset of NAT that supports two 
types of mapping, Many-to-One and Server. The P-660HWP-Dx also supports Full 
Feature NAT to map multiple global IP addresses to multiple private LAN IP addresses of 
clients or servers using mapping types as outlined in 

• Choose SUA Only if you have just one public WAN IP address for your P-660HWP-Dx.
• Choose Full Feature if you have multiple public WAN IP addresses for your P-660HWP-

Dx.

Some applications, such as SIP, cannot operate through NAT (are NAT un-friendly) because 
they embed IP addresses and port numbers in their packets’ data payload. 
Some NAT routers may include a SIP Application Layer Gateway (ALG). An Application 
Layer Gateway (ALG) manages a specific protocol (such as SIP, H.323 or FTP) at the 
application layer. 
A SIP ALG allows SIP calls to pass through NAT by examining and translating IP addresses 
embedded in the data stream. 
When the P-660HWP-Dx registers with the SIP register server, the SIP ALG translates the P-
660HWP-Dx’s private IP address inside the SIP data stream to a public IP address. You do not 
need to use STUN or an outbound proxy if your P-660HWP-Dx is behind a SIP ALG. 

Table 48   NAT Mapping Types

One-to-One

ILA1ÅÆ IGA1

Many-to-One (SUA/PAT)

ILA1ÅÆ IGA1
ILA2ÅÆ IGA1
…

Many-to-Many Overload

ILA1ÅÆ IGA1
ILA2ÅÆ IGA2
ILA3ÅÆ IGA1
ILA4ÅÆ IGA2
…

Many-to-Many No Overload

ILA1ÅÆ IGA1
ILA2ÅÆ IGA2
ILA3ÅÆ IGA3
…

Server

Server 1 IPÅÆ IGA1
Server 2 IPÅÆ IGA1
Server 3 IPÅÆ IGA1