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Double NAT, SPA122




When connecting Smartrg808 Wi-Fi modem directly to SPA122 it works fine .But when connecting SMartrg808 to another Wi-Fi router then to SPA122 it doesn't work with no dial tone.


Default gateway of Smartrg808 is

Default gateway of Wi-Fi router is


Even after removing the Wi-Fi router and connecting directly to SMARTRG808 modem , SPA122 was getting , I tried IVR reset and restarting BOTH till it got with a dial tone 


And when I replaced the Smartrg808 with Non-Wi-Fi modem Technicolor TC4350 , SPA122 worked fine (Technicolor to Wi-FI router  to SPA122).


I wonder why It doesn't work when the Wi-Fi router was in the connection , What can I do to use the Smartrg808 with the Wi-Fi router . 

And why it worked with Technicolor TC4350 and not Smartrg808


Thank you

1 Reply 1

Dan Lukes
VIP Alumni
VIP Alumni

You are expecting we are familiar with exact behavior of various kind of routers and we can guess it's configuration. Sorry, we can't.

Unless you know behavior of devices you are using, you need to analyze what's happening at network level. It require someone familiar with networking basic as well as basic knowledge of the SIP protocol. Ask your network administrator for help if you have skills required.


As a blind shot - either WiFi router uses SIP unfriendly NAT or the stack of the devices you chained creates it together.

Also a packet filter can cause issues.

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