External extension - using STUN

[kmedri]

Hi,We are trying to connect a Grandstream DP750 to 3CX v 15 externally using STUN

We connect the phone locally first in the office, 3CX finds the phone and we can provision via the FQDN
We then take the phone to the external location and it connects immediately, I can log into 3CX and see the phone connected via the IP address of the external location, we can make and receive phone calls. After approx 2 hours we loose the ability to call the phone, it goes straight to the voicemail and it is no longer connected in 3CX, we can still call out.

Any ideas?

 

[complex1]

Hi,

Using the DP750 is bad choice.
I had some similar issues with a DP715 so I replaced it with the Yealink W52P and all the issues where gone.

 

[kmedri]

Thank you Complex1, thats a real shame, we have inherited a couple of clients with a large number of phones, so is it that 3CX and Grandstream are not compatible?
I see my post was changed by a moderator and the word Grandstream taken out and replaced with "Unsupported IP Phone"

With these clients it will be too expensive to change the phones, so is my only option to change the PBX?

 

[leejor]

After approx 2 hours we loose the ability to call the phone, it goes straight to the voicemail and it is no longer connected in 3CX, we can still call out.

You say you can't call the phone. Does 3CX actually show it as unregistered? Does the 3CX activity log confirm that there are no re-registration attempts?


If it takes two hours to stop registering, then I would look to the set, to see if there is a solution, perhaps a setting that needs to be changed (STUN?). The default re-registration time used on 3CX is 30 minutes, which would suggest that your set is doing this, correctly,a number of times. So, the question is, what is happening (in the set) that abruptly stops that?

Perhaps it isn't the set, it may be the network(location) it is behind. Have you tried using the set at a different location? Have you tried running Wireshark, at the set end, to see if there is a correlation between when a STUN request is make (answered) and when re-registration stops.

 

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Is the phone setup for remote in 3cx pbx under provisioning?