Configure Nat Mapping With Stun - Cisco 8800 Series Manual

Cisco IP Phone Installation
Parameter
NAT Keep Alive
Enable
(Optional)

Configure NAT mapping with STUN

If the service provider network does not provide a Session Border Controller functionality and if the other
requirements are met, it is possible to use Session Traversal Utilities for NAT (STUN) to discover the NAT
mapping. The STUN protocol allows applications operating behind a network address translator (NAT) to
discover the presence of the network address translator and to obtain the mapped (public) IP address (NAT
addresses) and the port number that the NAT has allocated for the User Datagram Protocol (UDP) connections
to remote hosts. The protocol requires assistance from a third-party network server (STUN server) located on
the opposing (public) side of the NAT, usually the public Internet. This option is considered a last resort and
should be used only if the other methods are not available. To use STUN:
• The router must use asymmetric NAT. See
• A computer running STUN server software is available on the network. You can also use a public STUN
Before you begin
Access the phone administration web page. See
Procedure
Step 1
Select Voice > SIP.
Step 2 In the NAT Support Parameters section, set the Handle VIA received, Insert VIA received, Substitute
VIA Addr, Handle VIA rport, Insert VIA rport, and Send Resp To Src Port parameters as described in
the NAT Mapping with Static IP Parameters, on page 388
Step 3 Set the parameters as described in the
Step 4
Click the Ext(n) tab.
Step 5 In the NAT Settings section, set the parameters as described in the
IP Parameters
Description
Configured NAT keep alive message periodically.
Perform one of the following:
• In the phone configuration file with XML(cfg.xml), enter a string in this format:
<NAT_Keep_Alive_Enable_1_ ua="na">Yes</NAT_Keep_Alive_Enable_1_>
• In the phone web page, set to Yes to configure periodic NAT keep alive
messages.
Note
Allowed values: Yes and No.
Default: No
server or set up your own STUN server.
table.
Cisco IP Phone 8800 Series Multiplatform Phone Administration Guide for Release 11.3(1) and Later
The service provider might require the phone to send NAT keep
alive messages to keep the NAT ports open.
Check with your service provider to determine the requirements.
Determine Symmetric or Asymmetric NAT, on page
Access the Phone Web Interface, on page
table.
NAT Mapping with STUN Parameters
Configure NAT mapping with STUN
104.
table.
NAT Mapping from Ext Tab with Static
392.
391