Enabling DMZ causes Vonage to malfunction?

[OniOceans]

Hey there, I am trying to set my DMZ on my router to my computers address. I know the risks of doing this, but my problem is with our Vonage phones.
I'm not sure what causes this problem, or how to fix it for that matter.

The Problem: When DMZ is enabled, our Vonage phones are unable to receive sound from other callers, however, they can hear us just fine.

Is there some sort of VOIP setting I need to tweak? Any advice is welcomed.
Please and thank you!

If it helps:
Router: Netgear Nighthawk X6 R8000
Let me know if you need further information.

 

[BuddhaSkoota]

The Problem: When DMZ is enabled, our Vonage phones are unable to receive sound from other callers, however, they can hear us just fine.

With a PC in the DMZ, it's likely that the the ports required for Vonage service are not reaching the Vonage adapter. Port forwarding the proper ports should solve this problem.

 

[OniOceans]

The Problem: When DMZ is enabled, our Vonage phones are unable to receive sound from other callers, however, they can hear us just fine.

With a PC in the DMZ, it's likely that the the ports required for Vonage service are not reaching the Vonage adapter. Port forwarding the proper ports should solve this problem.

This was the perfect suggestion, everything is functioning perfectly now. I forwarded the ports that Vonage recommended and everything works. Thank you for the quick and accurate response!