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pa-0/dns-sync.sh

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Last active July 3, 2024 23:39
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  1. pa-0 revised this gist Jul 3, 2024. 1 changed file with 177 additions and 0 deletions.
    177 changes: 177 additions & 0 deletions original-gist-comments.md
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    #### @matthiassb commented on Jul 23, 2018 •
    Steps to run (as root)
    This init.d script will keep Ubuntu WSL dns config in-sync with windows with a 15 sec lag-time.

    >Be warned: If this service is not running and the nameservers in windows userspace changed, then you may lose connectivity in WSL - make sure the daemon is running at all times
    ```
    wget https://gist.github.com/matthiassb/9c8162d2564777a70e3ae3cbee7d2e95/raw/b204a9faa2b4c8d58df283ddc356086333e43408/dns-sync.sh -O /etc/init.d/dns-sync.sh
    chmod +x /etc/init.d/dns-sync.sh
    unlink /etc/resolv.conf
    service dns-sync.sh start
    ```

    Note: WSL does not support service auto-start, when you boot your system you'll need to start the service manually

    #### @regisbsb commented on Jul 23, 2018

    ```
    wget https://gist.github.com/matthiassb/9c8162d2564777a70e3ae3cbee7d2e95/raw/56640fbb50ec870d2a2f62b1f188081c29d45337/dns-sync.sh -O /etc/init.d/dns-sync.sh
    ```

    #### @matthiassb commented on Jul 23, 2018
    Disable Init.d and restore original WSL functionality (as root)
    service dns-sync.sh stop
    unlink /etc/resolv.conf
    ln -s /run/resolvconf/resolv.conf /etc/resolv.conf

    #### @matthiassb commented on Jul 23, 2018
    @regisbsb fixed

    #### @alexey-krylov commented on Nov 26, 2018 •
    It's possible to autostart this script with bash. Just add this lines to ~/.bashrc:

    if service dns-sync.sh status| grep -q 'dns-sync is not running'; then
    sudo service dns-sync.sh start
    fi

    #### @carm-scaffidi commented on Jan 19, 2019
    Thanks for the great tip to get this working!

    #### @estebarb commented on Feb 6, 2019
    The script enables networking with the outside world (yay!). Unfortunatelly, that script prevents Linux to connect to a local X Server, so I can't use a local xfce :(

    #### @matthiassb commented on Feb 25, 2019
    @estebarb. Can you elaborate a little more on your configuration/setup? I might be able to update this GIST to support this scenario.

    #### @BrianBlaze commented on Jul 4, 2019 •
    Thank you for this... weirdly enough using this I saw in task manager init using a ton of CPU%... I will just stick to manually configuring.

    #### @adrianohirata commented on Aug 20, 2019
    Weird... everytime the script runs it changes the font used in the WSL console window. Has anyone else seen this?

    #### @ghost commented on Sep 25, 2019 •
    Weird... everytime the script runs it changes the font used in the WSL console window. Has anyone else seen this?

    This seems to happen when PowerShell, called from bash (maybe other shells, too), in a WSL instance is instructed to redirect its stdout to a file.

    #### @sparcs360 commented on Nov 2, 2019
    A workaround for the font switching problem is explained here -> https://patrickwu.space/2019/08/03/wsl-powershell-raster-font-problem/

    #### @caiowilson commented on Nov 13, 2019
    congrats on the solution! I mean, REALLY!

    #### @Farix1337 commented on Dec 4, 2019
    you rock

    #### @faaarmer commented on Apr 16, 2020
    Still works fantastically. Thanks!

    #### @rroblik commented on May 18, 2020
    @matthiassb is this required https://gist.github.com/matthiassb/9c8162d2564777a70e3ae3cbee7d2e95#gistcomment-2769071?
    Seems to work without it and give me an error when enabled :)

    #### @jan-glx commented on Sep 23, 2020
    To prevent yourself from having to type your password every time you open a new shell after putting
    ```
    if service dns-sync.sh status| grep -q 'dns-sync is not running'; then
    sudo service dns-sync.sh start
    fi
    ```
    in your ~/.bashrc to start the service automatically as described by @alexey-krylov you can use the following lines to modify allow sudo users to modify the service without a password:
    ```
    echo -e "%sudo ALL=(ALL) NOPASSWD: /usr/sbin/service dns-sync.sh *\n%sudo ALL=(ALL) NOPASSWD: /usr/sbin/service dns-sync.sh\n" | sudo tee /etc/sudoers.d/dns-sync
    sudo chmod 0440 /etc/sudoers.d/dns-sync
    ```

    #### @AllanMedeiros commented on Oct 5, 2021
    This script seems to finally have fixed my DNS issues on Ubuntu 20.04 under WSL2! Thank you!
    Not sure why, but when the script is started, my terminal font changes...
    image

    #### @jan-glx
    jan-glx commented on Nov 12, 2021
    I needed to change line 22 to $PS -Command 'Get-DnsClientServerAddress -AddressFamily IPv4 -InterfaceIndex $(Get-NetIPInterface -AddressFamily IPv4 | Where-Object ConnectionState -EQ "Connected" | Sort-Object InterfaceMetric | Select-Object -ExpandProperty ifIndex) | Select-Object -ExpandProperty ServerAddresses' > $TEMPFILE to avoid DNS servers from disconnected interfaces showing up first

    #### @jarrodhroberson commented on Feb 27, 2023
    Does anyone have any updates to this.

    I started at the top and tried every thing listed as I went down the list of comments and nothing works.

    I still get this, I applied every mod/patch that everyone mentioned all the way down to jan-glx one at a time and nothing changed.

    I did wsl --shutdown after every change to make sure it was getting a fresh start and data.

    I still get:

    ```
    ❯ go mod tidy
    go: downloading github.com/spf13/cobra v1.6.1
    adotools/cmd imports
    github.com/spf13/cobra: github.com/spf13/[email protected]: Get "https://proxy.golang.org/github.com/spf13/cobra/@v/v1.6.1.zip": proxyconnect tcp: dial tcp: lookup my.corp.proxy.com: i/o timeout
    ```

    when I try to do sudo apt update all I get is:

    ```
    Temporary failure resolving 'my.corp.proxy.com'
    my.corp.proxy.com is anonymized obviously :-)
    ```

    Anything else anyone can think out would help.

    #### @cantti commented on Aug 29, 2023
    Now WSL2 supports systemd, so we can run script as a service.

    Download script to home directory

    ```
    wget https://gist.github.com/matthiassb/9c8162d2564777a70e3ae3cbee7d2e95/raw/b204a9faa2b4c8d58df283ddc356086333e43408/dns-sync.sh -O ~/dns-sync.sh
    chmod +x ~/dns-sync.sh
    ```

    Add these lines to the /etc/wsl.conf if not exists (sudo nano /etc/wsl.conf)

    ```
    [boot]
    systemd=true
    [network]
    generateResolvConf=false
    ```

    Reboot.

    Create a unit file

    ```
    sudo touch /etc/systemd/system/dns-sync.service
    Edit (sudo nano /etc/systemd/system/dns-sync.service) and fix path to script inside
    [Unit]
    Description=dns sync
    [Service]
    ExecStart=PUT_PATH_HERE
    Type=forking
    [Install]
    WantedBy=multi-user.target
    ```

    Reboot

    Run service

    ```
    sudo systemctl enable dns-sync.service
    sudo systemctl start dns-sync.service
    sudo systemctl status dns-sync.service
    ```

    #### @rroblik commented on Aug 31, 2023
    @cantti : enabling systemd prevent any .execommand to work, including the powershell command required by the script. That resulted in... an empty /etc/resolv.conf ! ❌

    Related interesting thread : https://www.reddit.com/r/bashonubuntuonwindows/comments/11vx61n/wsl2_error_cannot_execute_binary_file_exec_format/

    I'm looking for a workaround but for now I have to (re)disable systemd 😭
  2. @matthiassb matthiassb revised this gist Jul 23, 2018. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion dns-sync.sh
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    # Required-Stop:
    # Default-Start: S
    # Default-Stop:
    # Short-Description: Synchronizes /etc/resolv.conf in WLS with Windows DNS
    # Short-Description: Synchronizes /etc/resolv.conf in WLS with Windows DNS - Matthias Brooks
    ### END INIT INFO

    PATH=/sbin:/bin
  3. @matthiassb matthiassb created this gist Jul 23, 2018.
    92 changes: 92 additions & 0 deletions dns-sync.sh
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    #! /bin/bash
    ### BEGIN INIT INFO
    # Provides: dns-sync
    # Required-Start:
    # Required-Stop:
    # Default-Start: S
    # Default-Stop:
    # Short-Description: Synchronizes /etc/resolv.conf in WLS with Windows DNS
    ### END INIT INFO

    PATH=/sbin:/bin
    PS=/mnt/c/Windows/System32/WindowsPowerShell/v1.0/powershell.exe

    . /lib/init/vars.sh
    . /lib/lsb/init-functions

    do_start () {
    while true
    do
    #Retrieve nameservers from via Powershell
    TEMPFILE=$(mktemp)
    $PS -Command "Get-DnsClientServerAddress -AddressFamily IPv4 | Select-Object -ExpandProperty ServerAddresses" > $TEMPFILE
    /usr/bin/awk '!x[$0]++' $TEMPFILE > $TEMPFILE.2
    IFS=$'\r\n' GLOBIGNORE='*' command eval 'UNIQUE_NAMESERVERS=($(cat $TEMPFILE.2))'
    rm -f $TEMPFILE $TEMPFILE.2

    #Retrive search domains via powershell
    IFS=$'\r\n' GLOBIGNORE='*' command eval 'SEARCH_DOMAIN=($($PS -Command "Get-DnsClientGlobalSetting | Select-Object -ExpandProperty SuffixSearchList"))'
    UNIQUE_SEARCH_DOMAIN=($(/usr/bin/tr ' ' '\n' <<< "${SEARCH_DOMAIN[@]}" | /usr/bin/sort -u | /usr/bin/tr '\n' ' '))


    #Modify /etc/resolv.conf
    touch /etc/resolv.conf
    sed -i '/nameserver/d' /etc/resolv.conf > /dev/null 2>&1 || true
    sed -i '/search/d' /etc/resolv.conf > /dev/null 2>&1 || true

    for i in "${UNIQUE_NAMESERVERS[@]}"
    do
    echo "nameserver ${i}" >> /etc/resolv.conf
    done
    if [ ${#UNIQUE_SEARCH_DOMAIN[@]} -ne 0 ]; then
    echo "search ${UNIQUE_SEARCH_DOMAIN[@]}" >> /etc/resolv.conf
    fi
    sleep 15
    done
    }

    do_status () {
    PID=$(cat /var/run/dns-sync.pid 2>/dev/null)
    if [ "$PID" == "" ]; then
    echo "dns-sync is not running"
    return
    fi

    if ps -p $PID > /dev/null
    then
    echo "dns-sync is running"
    else
    echo "dns-sync is not running"
    fi
    }

    case "$1" in
    start|"")
    kill $(cat /var/run/dns-sync.pid >/dev/null 2>&1) > /dev/null 2>&1 || true
    do_start &
    DO_SYNC_PID=$!
    echo "${DO_SYNC_PID}" > /var/run/dns-sync.pid
    ;;
    restart|reload|force-reload)
    echo "Error: argument '$1' not supported" >&2
    exit 3
    ;;
    stop)
    PID=$(cat /var/run/dns-sync.pid)
    if ps -p $PID > /dev/null
    then
    kill -9 $(cat /var/run/dns-sync.pid)
    echo "dns-sync stopped"
    else
    echo "dns-sync is not running"
    fi
    ;;
    status)
    do_status
    exit $?
    ;;
    *)
    echo "Usage: dns-sync.sh [start|stop]" >&2
    exit 3
    ;;
    esac