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?