serial_lte_modem DNS resolution issues

[Mr.Newlove]

Hey all,

So I have been having inconsistent issues connecting to different domains, and after getting the debugger working it appears to be a DNS resolution issue and it never even tries to connect

All I really want is to change the DNS server the modem is using because whatever the carrier or software is deciding to use is just too unreliable.

A few relevant posts, but with out of date data:

https://devzone.nordicsemi.com/f/nordic-q-a/44294/using-getaddrinfo-for-dns-lookups-nrf9160-dk/177777#177777

https://devzone.nordicsemi.com/f/nordic-q-a/50029/nrf9160-modem-firmware-v1-0-0-setting-custom-dns-server/235139#235139

But neither of these point to anything usable with the serial_lte_modem or seemingly commands that no longer exist.

It is really hard to come up with a test case for you to use on your end since it seems to be tied to my local carrier. But it has been quite frustrating where the modem will work fine for hours, and then I reboot it or something and then it can no longer resolve many domains.

I tried adding this to prj.conf:

CONFIG_NET_NATIVE=y
CONFIG_DNS_RESOLVER=y
CONFIG_DNS_SERVER_IP_ADDRESSES=y
CONFIG_DNS_SERVER1="8.8.8.8"
CONFIG_DNS_SERVER2="1.1.1.1"

But it had no affect.

Thanks,

Kyle

[Mr.Newlove]

Another odd thing, that kinda confirms it being entirely a DNS problem. I didn't know this would work but I tried to convert the IP into a number and passed that instead of a domain and that worked, and oddly enough it seems to fix the DNS lookup for a short while as well?

ie:

AT#XFTP="open","******username********","*******password*****","****IP address as int****"

Edit: Spoke too soon, still fails for periods of time.