P-2302R Series VoIP Station Gateway User's Guide
Table Of Contents
- P-2302R Series
- User’s Guide
- Copyright
- Federal Communications Commission (FCC) Interference Statement
- Safety Warnings
- ZyXEL Limited Warranty
- Customer Support
- Table of Contents
- List of Figures
- List of Tables
- Preface
- Introducing the Prestige
- Introducing the Web Configurator
- Wizard Setup
- System Screens
- LAN Setup
- WAN Screens
- Introduction to VoIP
- VoIP Screens
- Phone
- Phone Book
- Phone Usage
- Network Address Translation (NAT) Screens
- Static Route
- Firewall
- Content Filtering
- Remote Management Screens
- Universal Plug-and-Play (UPnP)
- Logs
- Bandwidth Management
- 19.1 Bandwidth Management Overview
- 19.2 Bandwidth Classes and Filters
- 19.3 Proportional Bandwidth Allocation
- 19.4 Application-based Bandwidth Management
- 19.5 Subnet-based Bandwidth Management
- 19.6 Application and Subnet-based Bandwidth Management
- 19.7 Scheduler
- 19.8 Maximize Bandwidth Usage
- 19.9 Bandwidth Borrowing
- 19.10 Configuring Summary
- 19.11 Configuring Class Setup
- 19.12 Configuring Monitor
- Maintenance
- Introducing the SMT
- General Setup
- WAN Setup
- LAN Setup
- Internet Access
- Remote Node Configuration
- Static Route Setup
- Network Address Translation (NAT)
- Enabling the Firewall
- Filter Configuration
- SNMP Configuration
- System Information and Diagnosis
- Firmware and Configuration File Maintenance
- 33.1 Filename Conventions
- 33.2 Backup Configuration
- 33.2.1 Backup Configuration
- 33.2.2 Using the FTP Command from the Command Line
- 33.2.3 Example of FTP Commands from the Command Line
- 33.2.4 GUI-based FTP Clients
- 33.2.5 TFTP and FTP over WAN Management Limitations
- 33.2.6 Backup Configuration Using TFTP
- 33.2.7 TFTP Command Example
- 33.2.8 GUI-based TFTP Clients
- 33.3 Restore Configuration
- 33.4 Uploading Firmware and Configuration Files
- System Maintenance
- Remote Management
- Call Scheduling
- Troubleshooting
- 37.1 Problems Starting Up the Prestige
- 37.2 Problems with the LAN Interface
- 37.3 Problems with the WAN Interface
- 37.4 Problems with Internet Access
- 37.5 Problems with the Password
- 37.6 Problems with the Web Configurator
- 37.7 Problems with a Telephone or the Telephone Port
- 37.8 Problems with Voice Service
- 37.9 Pop-up Windows, JavaScripts and Java Permissions
- Product Specifications
- Wall-mounting Instructions
- Setting up Your Computer’s IP Address
- IP Subnetting
- PPPoE
- Triangle Route
- SIP Passthrough
- Index

P-2302R Series User’s Guide
99 Chapter 7 Introduction to VoIP
Figure 35 Symmetric NAT
7.4 NAT and SIP
The Prestige must register its public IP address with a SIP register server. If there is a NAT
router between the Prestige and the SIP register server, the Prestige probably has a private IP
address. The Prestige lists its IP address in the SIP message that it sends to the SIP register
server. NAT does not translate this IP address in the SIP message. The SIP register server gets
the Prestige’s IP address from inside the SIP message and maps it to your SIP identity. If the
Prestige has a private IP address listed in the SIP message, the SIP server cannot map it to your
SIP identity.
A SIP ALG (Application Layer Gateway) or the Use NAT, STUN, and outbound proxy
features allow the Prestige to list its public IP address in the SIP messages.
7.5 SIP ALG
Some NAT routers may include a SIP Application Layer Gateway (ALG). A SIP ALG allows
SIP calls to pass through NAT by examining and translating IP addresses embedded in the
data stream. When the Prestige registers with the SIP register server, the SIP ALG translates
the Prestige’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 Prestige is behind a SIP ALG.
7.6 Use NAT
If you know the NAT router’s public IP address and SIP port number, you can use the Use
NAT feature to manually configure the Prestige to use a them in the SIP messages. This
eliminates the need for STUN or a SIP ALG.
You must also configure the NAT router to forward traffic with this port number to the
Prestige.