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NTP and AT&T Network

Q&A Forum › Category: ESP32 › NTP and AT&T Network
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William Lucid asked 3 years ago

I have a project using NTP that works fine on “Xfinity” network with firewall configured.  Project on “AT&T” network does not receive NTP packets with same firewall configutration.  There is a routine in project to wait for a valid timestamp; project hangs at this point on the “AT&T” network.

I have read on the “AT&T Community Forum” that “AT&T” blocks NTP port 123.  Has anyone experienced this issue?  Is there a work around?

William

Question Tags: ESP32, NTP
8 Answers
0 Vote Up Vote Down
Sara Santos Staff answered 3 years ago

Hi.
I’m not familiar with this issue and I don’t know how to solve it.
Maybe the next discussion might help: https://forums.att.com/conversations/att-internet-equipment/options-to-get-ntp-time-since-att-blocks-port-123/600aebf9127141623b1faf67
Regards,
Sara

0 Vote Up Vote Down
William Lucid answered 3 years ago

Sorry for late response Sara; always appreciate your responses.
I have been able to use udp protocol on port 1337; here on Xfinity network.  Will give it a try when I get back over to the home that has AT&T network.
 
Thank you Sara,
William
 

0 Vote Up Vote Down
William Lucid answered 3 years ago

Update 1/15/2021; took project to home owner with AT&T router/gateway.

Still no joy; project to monitor sump pump uses NTP for scheduling events, Receives udp packets on port 1337.  I have been unable to get project to work with AT&T router/gateway.  Project using NTP port 1337 works on Xfinity router/gateway.  Need to do more research/googling…

 

Regards,
William

0 Vote Up Vote Down
Sara Santos Staff answered 3 years ago

Ok.
Thanks for the update.

0 Vote Up Vote Down
William Lucid answered 3 years ago

Looking over the code; found an error in configutation of AT&T network settings for both gateway and dns. I used “192.168.1.1” for both.  Gateway and dns both need to be “192.168.1.254”. Did not catch this earlier because it was connecting to the AT&T network using “static ipAddressing”.

Connected even with the wrong gateway and dns!

I will not be able to test until weekend; no access to AT&T network due to home owners schedule.

Regards,
William

0 Vote Up Vote Down
Sara Santos Staff answered 3 years ago

Thanks for the follow-up.
Then, tell us the results.
Regards,
Sara

0 Vote Up Vote Down
William Lucid answered 3 years ago

Update:  1/29/2022
Changing network gateway and dns to correct octets of “192.168.1.254”; instead of “192.168.1.1” has resolved the issue.
 
Learned from this issue; static ipAddressing  may say “connected” and still not be “talking” to gateway or resolving dns.
 
No longer “hanging” at “waiting for valid time stamp.”  NTP udp packets are being received. I used port forwarding of 1337; not port 123 for udp packets.
 
William

0 Vote Up Vote Down
Sara Santos Staff answered 3 years ago

Hi.
Thanks for sharing this information. It might be useful for other readers.
I’ll mark this issue as resolved.
Regards,
Sara

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