Hello,
This depends on what you are trying to achieve. Since LAN is always UP, specifying DNS servers on the LAN interface will basically mean that this DNS servers can always be used. When resolving rms.teltonika-networks.com, your normal DNS servers are used, i.e the ones in /tmp/resolv.conf.d/resolv.conf/auto. If none of the DNS servers can resolve rms.teltonika-networks.com, you will get an error that states ‘unable to resolve hostname’ or something similar, and you will not be able to connect to RMS. Usually, DNS servers are obtained from the operator if SIM card is used, and can also be seen in the list. When wired WAN is used, DNS servers are usually obtained via DHCP.
Kind Regards,