NRF9160 getaddrinfo() return DNS_EAI_SYSTEM and errno 0

RE: NRF9160 getaddrinfo() return DNS_EAI_SYSTEM and errno 0

loumay — Fri, 09 Jul 2021 15:44:32 GMT

Hi Håkon,

Thanks for the pointer.

Best regards,

Louis

RE: NRF9160 getaddrinfo() return DNS_EAI_SYSTEM and errno 0

Håkon Alseth — Fri, 09 Jul 2021 14:05:44 GMT

Hi Louis,

You can try x amount of times, and wait in between each retry, similar to this:

https://github.com/nrfconnect/sdk-nrf/blob/master/samples/nrf9160/gps/src/supl_support.c#L43-L60

Kind regards,

Håkon

RE: NRF9160 getaddrinfo() return DNS_EAI_SYSTEM and errno 0

loumay — Fri, 09 Jul 2021 13:46:37 GMT

I will have a closer look to the CEREG notifications then.

Any recommendations on how to handle saturated/slow network?

I can easily increase timeout values in our application layer, but I didn't found anything to increase the timeout for DNS request on getaddrinfo().

Would a retry until getaddrinfo() success be the best approach here?

Kind regards,

Louis

RE: NRF9160 getaddrinfo() return DNS_EAI_SYSTEM and errno 0

Håkon Alseth — Fri, 09 Jul 2021 07:54:41 GMT

I'm glad to hear that you found the source of the issue.

If you listen to CEREG notifications (or other similar AT command notifications), you should be able to find if there's any network related disconnections or similar.

Kind regards,

Håkon

RE: NRF9160 getaddrinfo() return DNS_EAI_SYSTEM and errno 0

loumay — Thu, 08 Jul 2021 15:35:36 GMT

Hi Håkon,

It looks like the issue was too many units running at the same location and connecting to the same tower. Local network became too slow and DNS request were failing consistently.

Thanks again for you quick reply and inputs.

Louis

RE: NRF9160 getaddrinfo() return DNS_EAI_SYSTEM and errno 0

Håkon Alseth — Thu, 08 Jul 2021 12:44:30 GMT

Hi,

Its the default return code for getaddrinfo:

https://github.com/nrfconnect/sdk-nrf/blob/v1.6.0/lib/nrf_modem_lib/nrf91_sockets.c#L502

the original return code from nrf_getaddrinfo() is translated to the above return.

I would recommend that you check the unit using at_host and run it in lte link monitor (which enables error messages etc.) to see if it returns anything out of the ordinary after AT+CFUN=1 has been issued.

Kind regards,

Håkon