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Deco and windows 10 NTP connection problem

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Deco and windows 10 NTP connection problem

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Deco and windows 10 NTP connection problem
Deco and windows 10 NTP connection problem
2021-04-03 12:28:51 - last edited 2021-04-03 12:30:42
Model: Deco M4  
Hardware Version:
Firmware Version: 1.4.3 build 20200918 rel. 74289

Good morning,

 

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. 

 

SETUP : 
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

 

PROBLEM:

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).

 

TROUBLESHOOTING:

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. 

SUSPICION: 

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? 
 

Regards,

File:
pakietyNTP.pdfDownload
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#1
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10 Reply
Re:Deco and windows 10 NTP connection problem
2021-04-08 09:16:49

@DecoDzUser 

Thank you very much for your kind feedback.

 I would like to forward your case to the senior engineers for further assistance and please have a check of your email box later.

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#2
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Re:Deco and windows 10 NTP connection problem
2021-04-15 08:44:30

@TP-Link I have a similar problem. I have deco M9(3x) and since november 2020 i cant sync the time on my desktop or laptop. Only via a connection with my mobile phone.

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#3
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Re:Deco and windows 10 NTP connection problem
2021-05-25 21:19:00

@DecoDzUser I have exactly the same problem (Deco M4). Is there any solution on this yet?

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#4
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Re:Deco and windows 10 NTP connection problem
2021-05-26 02:52:35

@KHu  @penicillin 

Hi, currently, the final reason for this issue has not been located yet;

Could you please help me check some information so that I could forward your case to the senior engineers already;

  1. Did most of the clients connected to Deco fail to sync with the NTP server?
  2. What is the time difference?
  3. Could you please go to http://tplinkdeco.net and check whether Deco has the correct time settings?
  4. Please also check whether there are any parental control settings on the APP, which might block the communication with the NTP server;

(if possible, please also try to temporarily turn off the firewall on the Deco to have a test;)

Thank you very much and wait for your reply.

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#5
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Re:Deco and windows 10 NTP connection problem
2021-05-26 06:55:06

@TP-Link Hi, 

1.Yes, both my win10 PCs. Laptop with wifi connection and desktop PC with fixed Ethernet connection

2.around max 30 seconds (manually set)

3.Yes, deco time is correct

4.No parental controls

 

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#6
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Re:Deco and windows 10 NTP connection problem
2021-05-26 07:38:03

@KHu 

Hi, What if the NTP server is setup automatically, how about the time difference or the laptop could not sync with time at all?

And what is your manually configured NTP server?

I guess if the laptop is connected to the ISP modem directly, or a different network, the auto time-sync would be correct?

 

Thank you very much.

 

 

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#7
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Re:Deco and windows 10 NTP connection problem
2021-05-26 07:53:47

@TP-Link with ntp automatic,  no sync at all.

I have tried several ntp sources, currently pool.ntp.org

Yes, with connection to different network (e. g. phone wifi hotspot), the auto sync is fine.

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#8
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Re:Deco and windows 10 NTP connection problem
2021-05-26 11:22:13

@KHu 

Thanksheart.

And your case has been forwarded to the senior engineers; please have a check of your email box.

Thank you very much.

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#9
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Re:Deco and windows 10 NTP connection problem
2021-06-13 11:46:46

Hello,
I want to add that on macbook the ntp synchornisation worked - it is setting the return port to some ranom high-number port, so my suspicion that deco is blacking the default NTP port for incoming traffic gets validated.

BUT recently I have gotten an information that on windows PC synchronisation started working (cannot check it right now). I have opned the ticket also with Microsoft Technician, so maybe they have released the fix?
Can other users try to vlalidate that? Update your windows and check NTP once more? Also can you try to connect a macOs device, where NTP implementation seems to not be bugged?

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#10
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Re:Deco and windows 10 NTP connection problem
2021-06-13 15:08:38

@DecoDzUser

Hi, my problem was seemingly caused by my local (fixed fibre) ISP.  It seems that they block the external ntp requests (haven't yet clarified the reasoning for this) and are just providing the ISP own ntp server. After configuring to use this local server, everything started to work..

So, I can confirm that with WIN10 PC, the ntp sync works. 

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#11
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Views: 1482

Replies: 10

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