Stun server and NAT

[brucejacobscisco]

I need to operate a public stun server for voice. I want to put it on the dmz and then static nat public ip's to its internal ip addresses. It needs to respond on its publc interface however it is failing because of the natting.

[htarra]

Refer to the ATA 186/188 administrator guide for information on STUN support.

http://www.cisco.com/en/US/docs/voice_ip_comm/cata/186_188/3_0/english/administration/guide/sip/SIP88CH4.html

Cisco devices use a different method to avoid having to use STUN in the first place, using the VIA: option so they can

register correctly with the SIP server. You'd configure this per this doc on the ATA:

Look under "receiver tagged VIA header"

http://www.cisco.com/en/US/products/hw/gatecont/ps514/prod_release_note09186a0080109764.html

To maintain NAT/PAT translation for a session, the Cisco ATA 186 can now be configured to periodically send dummy UDP packets to a server (the Cisco ATA 186 does not expect any response from the server).

Here's some NAT related information that may help you with your situation:

http://www.cisco.com/en/US/products/hw/gatecont/ps514/products_administration_guide_chapter09186a00800c4b87.html

(see "NAT Gateway" and "NAT/PAT Translation" )