Change DNS servers, wifi and mobile data

Br1 · 22 Apr 2023, 18:38

@domubpkm said in Change DNS servers, wifi and mobile data:

@Br1 typo error

fixed, thank you.

domubpkm · 22 Apr 2023, 18:44

This post is deleted!

Br1 · 10 Oct 2023, 22:11

---- UPDATE OTA-2 Focal ----
---- Stable Channel ----

Usual three steps :

1 - download (just tap) setdns-ota.2 from here

2 - open file manager, go to Downloads, tap setdns-ota.2.tar.gz and tap extract archive

3 - open terminal, type :

sudo Downloads/setdns-ota.2/setdns-ota.2.sh

and hit enter,

type 1 + enter to set Cloudflare servers
type 2 + enter to set OpenDNS servers
type 3 + enter to set custom servers (*)
type 4 + enter to restore default settings (Restore OS)
type 5 + enter to exit (OS unchanged)

Remember to "Restore OS" before the next OTA update !

set-dns is one single script, preview :

#!/bin/bash

# Make sure only root can run this script
if [ "$(id -u)" != "0" ]; then
   echo " - You must prepend 'sudo' !" 1>&2
   exit 1
fi

echo -e '\n- Set DNS servers / Restore default -\n' ;

rsv_cnf=/etc/resolv.conf ;

# these are Cloudflare's DNS servers
CLF_one=1.1.1.1
CLF_two=1.0.0.1

# these are OpenDNS servers
OPE_one=208.67.222.222
OPE_two=208.67.220.220

PS3='
Please enter your choice : '
options=("  Cloudflare  -      " "  OpenDNS     -      " "  Custom DNS  -      " "  Restore OS  -      " "  Quit        -      ")
select opt in "${options[@]}"
do
	case $opt in
	"  Cloudflare  -      ")
		# check resolv.conf
		if [ ! -L $rsv_cnf ] ;

		then

			# -------------------- runs if resolv.conf is a file --------------------

			# mount root in read/write mode
			mount -o remount,rw / ;

			# add it Cloudflare servers
			echo -e "# Cloudflare servers" > $rsv_cnf ; echo -e "nameserver $CLF_one" >> $rsv_cnf ; echo -e "nameserver $CLF_two" >> $rsv_cnf ;

			# remount root in read only mode
			mount -o remount,ro / ;

			echo -e '\n Cloudflare DNS are set up !\n'

			exit 0

		else

			# -------------------- runs if resolv.conf is a symbolic link --------------------

			# mount root in read/write mode
			mount -o remount,rw / ;

			# delete symbolic link
			rm /etc/resolv.conf ;

			# create file
			touch /etc/resolv.conf ;

			# add it Cloudflare servers
			echo -e "# Cloudflare servers" > $rsv_cnf ; echo -e "nameserver $CLF_one" >> $rsv_cnf ; echo -e "nameserver $CLF_two" >> $rsv_cnf ;

                       # remount root in read only mode
                        mount -o remount,ro / ;

			echo -e '\n Cloudflare DNS are set up !\n'

			exit 0

		fi

		;;

	"  OpenDNS     -      ")
		# check resolv.conf
		if [ ! -L $rsv_cnf ] ;

		then

			# -------------------- runs if resolv.conf is a file --------------------

			# mount root in read/write mode
			mount -o remount,rw / ;

			# add it Cloudflare servers
			echo -e "# OpenDNS servers" > $rsv_cnf ; echo -e "nameserver $OPE_one" >> $rsv_cnf ; echo -e "nameserver $OPE_two" >> $rsv_cnf ;

			# remount root in read only mode
			mount -o remount,ro / ;

			echo -e '\n OpenDNS servers are set up !\n'

			exit 0

		else

			# -------------------- runs if resolv.conf is a symbolic link --------------------

			# mount root in read/write mode
			mount -o remount,rw / ;

			# delete symbolic link
			rm /etc/resolv.conf ;

			# create file
			touch /etc/resolv.conf ;

			# add it Cloudflare servers
			echo -e "# OpenDNS servers" > $rsv_cnf ; echo -e "nameserver $OPE_one" >> $rsv_cnf ; echo -e "nameserver $OPE_two" >> $rsv_cnf ;

                       # remount root in read only mode
                        mount -o remount,ro / ;

			echo -e '\n OpenDNS servers are set up !\n'

			exit 0

		fi

		;;

	"  Custom DNS  -      ")
		# check resolv.conf
		if [ ! -L $rsv_cnf ] ;

		then

			# -------------------- runs if resolv.conf is a file -------------------- 

			# mount root in read/write mode
			mount -o remount,rw / ;

			echo -e "# Custom DNS servers" > $rsv_cnf ; 

                                        read -p " Type primary server : " priDN

					echo -e "nameserver $priDN" >> $rsv_cnf ;

					read -p " Type secondary server : " secDN

					echo -e "nameserver $secDN" >> $rsv_cnf ;

			# remount root in read only mode
			mount -o remount,ro / ;

			echo -e '\n Custom DNS are set up !\n'

			exit 0

		else

			# -------------------- runs if resolv.conf is a symbolic link --------------------

			# mount root in read/write mode
			mount -o remount,rw / ;

			# delete symbolic link
			rm /etc/resolv.conf ;

			# create file
			touch /etc/resolv.conf ;

			echo -e "# Custom DNS servers" > $rsv_cnf ;

                                        read -p " Type primary server : " priDN

                                        echo -e "nameserver $priDN" >> $rsv_cnf ;

                                        read -p " Type secondary server : " secDN

                                        echo -e "nameserver $secDN" >> $rsv_cnf ;

                       # remount root in read only mode
                        mount -o remount,ro / ;

			echo -e '\n Custom DNS are set up !\n'

			exit 0

		fi

		;;

	"  Restore OS  -      ")
			# mount root in read/write mode
			mount -o remount,rw / ;

			# delete file
			rm /etc/resolv.conf ;

			# recreate symbolic link
			ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf ;

                       # remount root in read only mode
                        mount -o remount,ro / ;

			echo -e '\n Default settings have been Restored !\n'

			exit 0

		;;
        "  Quit        -      ")
			echo -e '\n  - OS unchanged !\n'

			break
		;;
			*) echo "invalid option $REPLY"
		;;
    esac
done

(*) For example, if you want to set Google DNS servers enter 8.8.8.8 as primary server and 8.8.4.4 as secondary server.

domubpkm · 13 Nov 2023, 20:46

@Br1 Hello. is your OTA-2 work / procedure the same for OTA-3 ? Thanks again

Br1 · 14 Nov 2023, 12:28

I can’t test ota 3 update, install at your own risk (*)

Br1 · 15 Nov 2023, 13:07

OTA 3 Stable channel --- You can reinstall, no changes are necessary.

domubpkm · 15 Nov 2023, 22:35

@Br1 Done, it works as expected.

domubpkm · 24 Jan 2024, 02:52

@Br1 I am on RC test OTA-4, it seems ok for me.

domubpkm · 1 Feb 2024, 23:20

@Br1

New tests.

I noted this:
. Sometimes a reboot is necessary to get my carrier's DNS fully restored if I no longer want to use cloudflare dns. Just using the 'restore' option in the script is not enough.

. When using cloudflare, in the list of cloudflare DNS servers, some are in the USA (Missouri). Is this normal ? Shouldn't cloudflare DNS all stay in its country of origin like I see with Firefox (all in France for me) ?

Thank you to enlighten me.

Br1 · 1 Feb 2024, 23:20

@domubpkm said in Change DNS servers, wifi and mobile data:

Sometimes a reboot is necessary to get my carrier's DNS fully restored

It could be caused by dns cache, after restoring try this :

sudo resolvectl flush-caches

if it works, I can add it to next version

@domubpkm said in Change DNS servers, wifi and mobile data:

Shouldn't cloudflare DNS all stay in its country of origin

servers in 120+ countries ... I don’t know what criteria they use

domubpkm · 2 Feb 2024, 00:46

@Br1 said in Change DNS servers, wifi and mobile data:

It could be caused by dns cache, after restoring try this :

sudo resolvectl flush-caches

Sorry, i can't confirm it works for me. A reboot is yet necessary.

@Br1 said in Change DNS servers, wifi and mobile data:

Shouldn't cloudflare DNS all stay in its country of origin

servers in 120+ countries ... I don’t know what criteria they use

When i did my precedent feedback, i was in RC TEST OTA-4. Now i am on 'real' OTA-4 and all cloudfare DNS are in my country. So for this, it's solved.

Br1 · 11 Feb 2024, 13:52

--- New version (only an optimization) here, as reported by @domubpkm to restore the original dns servers reboot is required (added message).