Deco and windows 10 NTP connection problem
I have invested in tp-link Deco system by buying 2x M4 units, 1x M3W extender and tp-link switch. I was happily using Deco since December 2020, no particular problems discovered.
The topology is as follows:
- Modem+Router provided from ISP
- main M4 deco connected to router with switch in between via ethernet cable. It is working in Access Point mode.
- Second M4 deivice connected with main Deco via ethernet backhaul with the same switch in between.
- M3W extender just extending Deco wifi
Week ago we have introduced new windows laptop to the network (wifi connection). We have quickly realized that date is not being synchronized via Internet. Setting different servers does not help.
While synchronisation worked on old Windows laptops, after changing the server to different one synchronisation stopped working there too.
So at the end, now all windows laptops connected to wifi are not synchronising with time.windows.com, pool.ntp.org or ntp.icm.edu.pl (we are in Poland).
Connecting to other network (like wifi tethered from phone) makes NTP synchronisation to work.
When we connect by cable to our tplink switch (thus connecting directly to router) the synchronisation works too.
I am attaching wireshark output of our test. First 2 packets are successful ones (cilient - server) when we were on tethered network. All other were send while on Deco network.
Windows is sending the request to the server to 123 port (standard NTP) but also setting the source port as 123, thus server response is meant to arrive at 123 port on our network. Maybe DECO recently blocked incoming 123 UDP requests because they may be used for DDoS amplification attack?
How can I further troubleshoot this problem?