NTP with time1.google.com not working

[ebaruk_673045617504343]

I'm using my "Reolink Video Doorbell PoE"....
And having problems with NTP syncing. I tried internally and externally (time1.google.com) but it doesn't help in any way..
All my firewall ports (UDP/123) are open (VLANS, WAN,.....).. But every time I try to sync it fails...

I have 6 cameras:

• 5 HIKVISON
• 1 REOLINK DOORBELL

All CAM settings are identical (same VLAN, same gateway, same DNS, same NTP server time1.google.com ...)

• The only difference are the static IP's of course but in the same subnet x.x.60.y)

If I test NTP sync on HIKVISION it works fine, but with REOLINK it allways fails...
Can someone suggest what to try more... I pretty much tried everything (package capturing,... )
And I'm not newbie in NETWORKING!

[joseph_1979]

@ebaruk_673045617504343 I tried it on RLC-511WA and it did synchronize. Try to capture a Wireshark trace at the egress of the router.

First I checked it from PC as illustrated below.

C:\>w32tm /stripchart /computer:time1.google.com /dataonly /samples:5
Tracking time1.google.com [216.239.35.0:123].
Collecting 5 samples.
The current time is 13/03/2024 11:27:11.
11:27:11, +01.3657866s
11:27:14, +01.3664224s
11:27:16, +01.3666259s
11:27:18, +01.3672233s
11:27:20, +01.3593511s

[Crimp On_62210811129]

Very strange. When I set the NTP server on a Reolink camera to time1(dot)google(dot)com, it synchronizes correctly.
(When I set the NTP server to garbage(dot)com, it fails - as it should because that is not an NTP server.)
I agree that capturing the actual packets is the best way forward. Either the doorbell sends the request using port 123 or it doesn't.

Mention of VLAN in the problem description "raises a flag" for me. Reolink cameras are like most consumer devices. They have no concept of VLAN tagging. What sort of network are these cameras part of?