Multiple 504G behind NAT

[azher.amin]

Hello,

I have two 504G phones behind NAT gateway to a service provider. One of the phone works for incoming/outgoing. Second phone works for outgoing but not incoming ...

Are there set of instructions avaiable for behind NAT scenarios ? I have used these instructions : http://www.3cx.com/sip-phones/cisco-SPA50XG.html

Is it required to use STUN ?

Thanks

-Azher

[nseto]

Not required to use stun.

You can set up the other NAT support parameters, such as EXT IP to put your router's ip address there and using the handle and insert VIA settings.

Or if your router has a checkbox for handling SIP, sometimes called SIP ALG.

Your service provider may also handle this issue.   Inquire with them if they use the 'outbound proxy' parameter.