[GH-ISSUE #167] Feature request: make NTP-server configurable #3398

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sascha_hemi · 2026-03-20T23:05:13+01:00

sascha_hemi commented

2026-03-20 23:05:13 +01:00

Originally created by @ThinkPadNL on GitHub (Nov 23, 2023).
Original GitHub issue: https://github.com/OpenEPaperLink/OpenEPaperLink/issues/167

It seems that the NTP-server is hardcoded. In my firewall i have blocked all internet traffic for my IOT vlan. I see outgoing NTP-requests to internet. I have a NAT-rule to bend them around to my internal NTP-server, but i would prefer to have it configured correctly on the client.

Would it be possible to add this in the wifi settings?

Originally created by @ThinkPadNL on GitHub (Nov 23, 2023). Original GitHub issue: https://github.com/OpenEPaperLink/OpenEPaperLink/issues/167 It seems that the NTP-server is [hardcoded](https://github.com/jjwbruijn/OpenEPaperLink/blob/220b4ae3e84e55ea78442e39e506e04907b33929/ESP32_AP-Flasher/src/system.cpp#L18). In my firewall i have blocked all internet traffic for my IOT vlan. I see outgoing NTP-requests to internet. I have a NAT-rule to bend them around to my internal NTP-server, but i would prefer to have it configured correctly on the client. Would it be possible to add this in the wifi settings?

sascha_hemi commented

2026-03-20 23:05:13 +01:00

@coelner commented on GitHub (Dec 6, 2023):

maybe this would be an option? : https://github.com/espressif/arduino-esp32/issues/2483

sntp_servermode_dhcp(1); //try to get the ntp server from dhcp
sntp_setservername(1, "europe.pool.ntp.org"); //fallback server
sntp_init();

@coelner commented on GitHub (Dec 6, 2023): maybe this would be an option? : https://github.com/espressif/arduino-esp32/issues/2483 ``` sntp_servermode_dhcp(1); //try to get the ntp server from dhcp sntp_setservername(1, "europe.pool.ntp.org"); //fallback server sntp_init(); ```

sascha_hemi commented

2026-03-20 23:05:13 +01:00

@nlimper commented on GitHub (Jan 10, 2024):

it's a pretty specific situation. I'm not going to work on this, but if somebody wants to add this and test it, I will merge it.

@nlimper commented on GitHub (Jan 10, 2024): it's a pretty specific situation. I'm not going to work on this, but if somebody wants to add this and test it, I will merge it.

sascha_hemi commented

2026-03-20 23:05:13 +01:00

@nerdyscout commented on GitHub (Jan 17, 2024):

yesterday I was working the very first time with the NanoAP noticing it is very laggy, did not really respond, took a long time to boot up. Skimming through the code and checking the serial output I noticed issues with the NTP server, one of them was not available at all, one was very slow, the third was ok. So I quickly removed the two of them and everything was better. I am not really sure yet what is a good way to permanently fix this issue... I just wanted to let you know there might be really a thing.

@nerdyscout commented on GitHub (Jan 17, 2024): yesterday I was working the very first time with the NanoAP noticing it is very laggy, did not really respond, took a long time to boot up. Skimming through the code and checking the serial output I noticed issues with the NTP server, one of them was not available at all, one was very slow, the third was ok. So I quickly removed the two of them and everything was better. I am not really sure yet what is a good way to permanently fix this issue... I just wanted to let you know there might be really a thing.

sascha_hemi commented

2026-03-20 23:05:14 +01:00

@ThinkPadNL commented on GitHub (Feb 26, 2024):

I have sold all my ESL hardware (not enough time to tinker with ih) so i think it is fair to also close this request as i won't be using this project anymore.

@ThinkPadNL commented on GitHub (Feb 26, 2024): I have sold all my ESL hardware (not enough time to tinker with ih) so i think it is fair to also close this request as i won't be using this project anymore.

sascha_hemi commented

2026-03-20 23:05:14 +01:00

@VincentKueszter commented on GitHub (Mar 13, 2026):

I have the same issue as the original author and I think that taking NTP servers from DHCP (or making them configurable at least) is a basic feature for any well-behaved network device.
I also noticed that if I lose the internet connection (or block it), the device hammers my local unbound instance with unreasonably frequent requests for the three hardcoded DNS servers - this could be avoided as well (i.e. by setting a local NTP server).

(the numbers are per minute)

I would be happy if this ticket could be reopened. I also would be more than willing to test a fix on my device - I tried implementing a fix myself, but that didn't work out.

@VincentKueszter commented on GitHub (Mar 13, 2026): I have the same issue as the original author and I think that taking NTP servers from DHCP (or making them configurable at least) is a basic feature for any well-behaved network device. I also noticed that if I lose the internet connection (or block it), the device hammers my local unbound instance with unreasonably frequent requests for the three hardcoded DNS servers - this could be avoided as well (i.e. by setting a local NTP server). <img width="516" height="342" alt="Image" src="https://github.com/user-attachments/assets/6d39b625-9396-4b20-8085-4aa28f83b9cc" /> (the numbers are per minute) I would be happy if this ticket could be reopened. I also would be more than willing to test a fix on my device - I tried implementing a fix myself, but that didn't work out.

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Reference: starred/OpenEPaperLink#3398