nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Syed Maysum Abbas Zaidi — Mon, 29 Jun 2026 09:00:01 GMT

Hi,

Unfortunately, its not in plan for the nRF9151.

Best Regards,
Syed Maysum

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Achim Kraus — Thu, 25 Jun 2026 15:49:35 GMT

Also not for the nRF9151?

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Syed Maysum Abbas Zaidi — Thu, 25 Jun 2026 10:52:58 GMT

Hi,

I am would just like to mention that this could be a feature for nRF92 (Still not confirmed). But will not be added for nRF91.

Best Regards,
Syed Maysum

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Syed Maysum Abbas Zaidi — Wed, 24 Jun 2026 14:32:22 GMT

Hi,

Thanks a lot its working now. Will forward it to R&D to analyze it further.

Best Regards,
Syed Maysum

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Achim Kraus — Wed, 24 Jun 2026 13:54:09 GMT

devzone.nordicsemi.com/.../dns_2D00_velocity.pcapng.gz

It's also dead on my side, next try ...

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Syed Maysum Abbas Zaidi — Wed, 24 Jun 2026 09:55:25 GMT

Hi,

Thanks for your message, this link seems to be dead as it says page no longer exists. Does this works at your end?

Best Regards,
Syed Maysum

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Achim Kraus — Wed, 24 Jun 2026 09:13:39 GMT

I know, that the 1.3.7 is "finalized", but improve the 2.0.4 would be helpful as well.

I only have an old capture, but no related modem trace.

(edited: removed dead link.)

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Syed Maysum Abbas Zaidi — Wed, 24 Jun 2026 08:04:36 GMT

Hi,

I would like to update that our R&D is actively looking in this issue so would like to ask if you can share the modem log/trace for it. We completely understand that the operator has already fixed this by changing the DNS server so it may not be reproducible but asking just in case it's possible.

However please note that we are not implementing this to nRF9160 / MFW 1.3.x, but can surely plan for upcoming products. Thanks.

Best Regards,
Syed Maysum

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Syed Maysum Abbas Zaidi — Fri, 12 Jun 2026 07:59:48 GMT

Hi,

Your request has been noted and we will definitely check what could be done at our end. Thanks a lot.

Best Regards,
Syed Maysum

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Achim Kraus — Thu, 11 Jun 2026 17:14:13 GMT

I still feel, that the limitation around DNS are better to be removed.

But for now, the ticket could be closed.

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Syed Maysum Abbas Zaidi — Thu, 11 Jun 2026 07:16:17 GMT

Hi,

Thanks a lot for your update and glad that the SIM provider managed to fix this behavior. Do let me know if it's fine to close this ticket.

Best Regards,
Syed Maysum

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Achim Kraus — Thu, 11 Jun 2026 05:56:48 GMT

Just as update:

Finally the MVNO (SIM provider) managed it to fix the behavior of their DNS service.

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Achim Kraus — Wed, 20 May 2026 05:01:01 GMT

Thanks for your answer.

While the issue itself isn't that hard (exchanging the SIM or modem will help), let me express, that my concern is the general way to handle such things.

As user I'm now faced two parties: the one who explains, that a second DNS is common and overcomes the issue. And the other party sticks to the DNS provided by the SIM and with that the means to escape are blocked.

Without "deep dive" into DNS (RFC 1035) and the common practice (here the use of the TC flag) it's hard to see, what is the "intended interoperable" way to go.

To propose to implement the DNS lookup by my self is then something, what I would understand for short term.

But for mid or long term, I would expect, that it gets possible to set the DNS server, regardless what the SIM card provides. For me this is not about, what is the right way, it's about having means to handle the situation in time.

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Syed Maysum Abbas Zaidi — Tue, 19 May 2026 14:51:35 GMT

Hi,

Thanks for detailed description. Your understanding of the fallback DNS is correct and since your SIM actively provides 1.1.1.1 as the primary DNS, setting CONFIG_LTE_LC_DNS_FALLBACK_ADDRESS="8.8.8.8" will have no effect on normal lookups, as it applies when the network provided DNS is missing. There seems no supported API to replace operator provided DNS servers while using the modem's offloaded getaddrinfo(). However you may try following options:

Try sending a raw DNS query over UDP directly to 8.8.8.8 using a normal offloaded UDP socket, bypassing the modem's DNS client entirely. This does not require disabling socket offloading and avoids the truncation issue. You can implement a retry, try 1.1.1.1 first and fall back to 8.8.8.8 if it fails.
Moreover it could be possible to use Zephyr's native DNS resolver with a specific server in principle but may it will not be a straight forward or a recommended option.

And it seems logical that a 86 byte response would not normally trigger truncation. To check what happens on failure, can you share modem trace. Thanks

Best Regards,
Syed Maysum

RE: nRF9160 - mfw 1.3.7 - NCS 3.2.4 - DNS lookup fails with some SIM cards using cloudflare

Achim Kraus — Tue, 19 May 2026 05:24:01 GMT

Follow up question:

Is it possible, to not use the "off-loading" just for the getaddrinfo?