nRF9160 Modem Firmware v1.0.0: Setting custom DNS server

[ntv1000]

Hello,

The release-notes of the Modem Firmware v1.0.0 for the nRF9160 state that there is now "Support for DNS server address setting by application.". However, I cannot find how to actually use this feature anywhere.

Is there perhaps an AT-command that is not documented yet? I'm looking at the AT Command Reference v1.0.

Can someone please help me out?

[Didrik Rokhaug]

Hi, and apologies for the slow response, but with summer vacations here in Norway it has been hard to find someone able to answer this question.

Sadly, while the modem supports setting of custom DNS server address, there is no support for this on the application side.

Best regards,

Didrik

[Andrey Dodonov]

Hi, this is also quite important for us.

Any update on this one?

All currently available Release Notes state that it IS possible (even with 'Support for 4 DNS server addresses.')
(Versions 1.0.0 through 1.1.1)

I tried command AT+CDNSCFG but it does not seem to be supported, I get an error back.
AT+CGCONTRDP also return empty strings for DNS addresses.

It is really vital for our project, our electrical engineers chose NRF91 because of quite impressive low power charactersistics, but we really need to get DNS resolving working!

Thank you!

[Didrik Rokhaug]

Hi.

With NCS v1.2.0 setting a custom DNS server address should now be possible.

Take a look at the release notes and bsdlib documentation:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/bsdlib/doc/CHANGELOG.html

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/bsdlib/doc/api.html#_CPPv414nrf_setdnsaddriPKv

Best regards,

Didrik

[Andrey Dodonov]

Hi, thank for you for a quick reply! 

Is there any info on using that?

nrfxlib/bsdlib/include/nrf_socket.h states that the first argument is IP family, which is according to 
https://www.iana.org/assignments/address-family-numbers/address-family-numbers.xhtml
should be 1 for IP4, but then the funciton gives back error 22 (invalid parameter).

With 2 it gives back 0 error code, but then AT+CGCONTRDP=0 still shows that DNS is not set, and getaddrinfo results in error 60 (timeout).

I am trying to use OpenDNS (208.67.222.222 and 208.67.222.220), obviously converted to uint32, as the function requires.

So, any example (even small code snippet) on how to set OpenDNS addresses would be HIGHLY APPRECIATED. Ideally both (primary and secondary), but this function states that it sets only secondary... But at least something to get DNS working.

Thank you so much!

P.S. Source code of this function is not open source, or? Then we could look into implementation/used AT command and not bother you.

But it looks like controlling the modem happens not just via AT commands.

[Andrey Dodonov]

Hello,

it worked with GoogleDNS! (8.8.8.8).

Now DNS resolving is working.

#include <nrf_socket.h>

struct nrf_in_addr dns;
dns.s_addr = 134744072; // Google DNS, 8.8.8.8
const int err = nrf_setdnsaddr(2, &dns);
printk("DNS set result %d\n", err);

It can be called before the rest of modem configuration, i.e. before w_lte_lc_init in lte_lc.c

However:

1) I needed to give 2 as first parameter, not 1.

2) AT+CGCONTRDP=0 still shows only APN set, no DNS

3) I would expect it to work with various DNS Servers, including OpenDNS  (208.67.222.222 and 208.67.222.220)