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?
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
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,
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…
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.
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.