I am experiencing an issue with DNS dynamic updates on a Windows Server DNS/DHCP environment when Teltonika devices operate as DHCP clients.
Context :
The Windows DHCP server assigns an IP address to the Teltonika device correctly.
However, the corresponding DNS records (A/AAAA and PTR) are not created or updated automatically via Dynamic DNS Updates.
Windows DHCP and DNS rely on the mechanism defined in RFC 2136 (“Dynamic Updates in the Domain Name System”), which is also used by BIND (via nsupdate).
When using an OpenWrt device as a DHCP client, DNS updates on Windows Server work out of the box, which confirms that the server-side DNS/DHCP configuration is functioning normally.
This suggests that the Teltonika DHCP client is either not sending the proper FQDN information (DHCP Options 12/81), or is not initiating a compliant dynamic DNS update process.
Our devices do not support option 81 as clients, only as servers. However, the option 12 is being sent (we double checked it via Wireshark), so what you can do as a workaround, is edit your WAN interface (since that’s how you’re probably receiving an IP address in the first place) and change the Hostname to send when requesting DHCP:
Could you share the OpenWRT version you’re currently using on the other router, as well as the network configuration & the dns/DHCP-related configurations? There shouldn’t be a difference in how these things work between RutOS and OpenWRT, so we would just like to confirm these details.
Thank you for the details. I’ll go ahead and contact our R&D to see what they have to say on this situation. Will get back to you as soon as I have an answer.
