Linksys ATA Administration Guide
40
Network Address Translation (NAT) and Voice over IP (VoIP)
Configuring Your System for ITSP Interoperability
6. Click
Submit All Changes
.
NOTE:
You also need to configure the firewall settings on your router to allow SIP traffic. See
”Firewalls and SIP,” on page 42
.
Configuring NAT Mapping with STUN
If the ITSP network does not provide a Session Border Controller functionality, and if other
requirements are met, it is possible to use STUN as a mechanism to discover the NAT mapping.
This option is considered a practice of last resort and should be used only if the other methods
are unavailable.
Requirements:
•
STUN is a viable option only if your router uses asymmetric NAT. See
”Determining
Whether the Router Uses Symmetric or Asymmetric NAT,” on page 41
.
•
You must have a computer running STUN server software.
•
The LAN switch must be configured to enable Spanning Tree Protocol and Port Fast on
the ports to which the SPA devices are connected.
NOTE:
Use NAT mapping only if the ITSP network does not provide a Session Border
Controller functionality.
1. Connect to the administration web server, and choose Admin access with Advanced
settings.
2. Click
Voice tab > SIP
.
3. Scroll down to the
NAT Support Parameters
section, and then enter the following settings to
enable and support the STUN server settings:
•
Handle VIA received:
yes
•
Handle VIA rport:
yes
•
Insert VIA received:
yes
•
Insert VIA rport:
yes
•
Substitute VIA Addr:
yes
•
Send Resp To Src Port:
yes
•
STUN Enable
: Choose
yes
.
•
STUN Server:
Enter the IP address for your STUN server.
