Nighthawk R8500 - NTP failing in the DMZ


Nighthawk R8500 - NTP failing in the DMZ

So here is a weird problem im having.


When my Nighthawk R8500 is behind my UVERSE modem not in the DMZ, then I see the time is received correctly after a reboot through, "NTP [Time synchronized with NTP server] Sunday, Feb 19,2017 07:10:58". If I reboot the 8500 for any reason, the time is maintained through NTP.


If I place the router in the UVERSE DMZ and dont reboot the 8500, but just Test the internet setup, the 8500, after 1 minute, picks up the public IP address and the time remains correct. All my clients work correctly and I can access the 8500 VPN service.


Now for any reason, whether through power failure or manual reboot, when the router comes back online, UVERSE still shows the 8500 in the DMZ and most of my clients work correctly, except the cloud based devices, my wireless link to my devices down stairs and my VPN service. If I check the time on the 8500, the date and time resets to January 1 00:00. I then see this message in the log, "[OPENVPN] NTP sync time failed. Get correct system time then reconnect".


To correct the problem, I have to reset the DMZ in the UVERSE modem, run an internet test on the 8500 (without a reboot on the 8500) , wait for the 8500 to receive UVERSE ip address (, wait for the NTP message in the logfile of the 8500. At that point I can activate DMZ on the UVERSE/8500 combination, get the external IP and the time in the 8500 remains correct. All the cloud based devices and the VPN work correctly again.


The 8500 will run flawlessly from this point until an external event like a power out, or an issues where UVERSE has to be rebooted either locally or when AT&T is upgrading their modem, then the whole process above needs to be redone.

Model: R8500|Nighthawk X8 Tri-Band AC5300 WiFi Router
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Re: Nighthawk R8500 - NTP failing in the DMZ

It sounds more like a problem with the UVerse modem than with the Netgear.  Do you, by any chance, have port forwarding for port 123 configured on the UVerse modem?  Port 123 is used by NTP.

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