Cisco Systems WRP400 Telephone Accessories User Manual


 
Configuring Your System for ITSP Interoperability
Network Address Translation (NAT) and Voice over IP (VoIP)
ATA Administration Guide 50
3
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 52.
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.
STEP 1 Connect to the administration web server, and choose Admin access with
Advanced settings.
STEP 2 Click Voice tab > SIP.
STEP 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.