Upgrading from WSL1 to WSL2 breaks custom hostnames

[sylfabre]

Environment

Windows build number: Microsoft Windows [Version 10.0.19041.450]
Your Distribution version: Ubuntu 20.04
Whether the issue is on WSL 2 and/or WSL 1: WSL 2

Steps to reproduce

1. Install Ubuntu 20.04 with WSL 1

2. Install Apache2 in WSL

sudo apt-get install apache2

3. Create an hello world file in Windows

#/mnt/c/www/index.html
Hello world!

4. Configure a virtual host

# /etc/apache2/sites-enabled/custom.conf

Listen 0.0.0.0:80

<VirtualHost *:80>
    ServerName localhost
    DocumentRoot /mnt/c/www

    <Directory "/mnt/c/www">
        AllowOverride All
        Require all granted
    </Directory>
</VirtualHost>

5. Reload Apache2

sudo service apache2 restart

6. Install (Acrylic DNS)[https://mayakron.altervista.org/support/acrylic/Home.htm] to define wildcard subdomain as local hosts.

# Acrylic hosts file
127.0.0.1 *.test.tld

7. Configure Acrylic to bind port 55 instead of 53 to free the 53 for WSL2 (as reported here WSL2 fails to start following 18965 update #4432 (comment))

# Acrylic conf file
LocalIPv4BindingPort=55
LocalIPv6BindingPort=55

8. Restart Acrylic

9. Install Yoga DNS

10. Define Acrylic as a DNS server for Yoga DNS
    

11. Define a Yoga DNS rules to route DNS queries to Acrylic for *.test.tld
    

12. Check browsing to http://local.test.tld works in Chrome

13. Upgrade your WSL to version 2 in PowerShell as admin

wsl --set-version Ubuntu-20.04 2

14. Restart Apache in WSL 2

sudo service apache2 start

Expected behavior

Chrome still displays a page at http://local.test.tld

Actual behavior

Chrome displays an error page at http://local.test.tld "ERR_CONNECTION_REFUSED"

Additionnal information

• It works if you define the following (mind the localhost as the first hostname on 2nd line cf Cannot connect to 127.0.0.1, localhost, or linux IP address #4353 (comment)) but you cannot have wildcard

# c:\windows\system32\drivers\etc\hosts
127.0.0.1 local.test.tld
::1 localhost local.test.tld

• Accessing http://localhost/ works in Chrome in WSL2

• Using the WSL 2 with the IP found with ip addr | grep eth0 does not work neither with:

• A ping from Windows
• In the Windows hosts file
• In Acrylic hosts file

[stevebovy]

WSL2 Wish-List Feature Fix ??

PROBLEM DESCRIPTION: "DOUBLE TROUBLE"

NON UNIQUE WSL2 HOST NAME CREATES UNNECESSARY "NAME RESOLUTION" CONFUSION WHICH CAN CURRENTLY ONLY BE WORKED

AROUND BY USING FULLY-QUALIFIED HOST NAME

Example of problem (Accessing Windows Host X-Serv)

The following will not work: DISPLAY=HOSTNAME:0

THE WORK AROUND IS DISPLAY=HOSTNAME.WINHOST-DOMAIN:0

Additional wsl.conf Network Keywords ??

Allow custom configuration of HOSTNAME file so that WSL2 VM machine network name is unique and different from windows

host machine name ( I would prefer the default to be the linux distribution name ) this would of course impact the HOST file as well

[Biswa96]

I am not sure if this feature is documented or available in stable Windows OS versions. For my case, I have tried this in latest Windows Insider build and it works. Create a /etc/wsl.conf file in your preffered WSL-ed GNU/Linux distribution. Add the following two lines in that /etc/wsl.conf file.

[network]
hostname = HelloWorld

Change the host name as you want.

[therealkenc]

[network]
hostname = HelloWorld
Change the host name as you want.

That doesn't expose the hostname to Windows. Whether that is by-design or WIP I can't say.

[Biswa96]

In /etc/hosts file, 127.0.1.1 is assigned to the host name. It can be used somehow.

[therealkenc]

The somehow is you can gethostbyname(3) in WSL. Fornow.

[therealkenc]

Chrome displays an error page at http://local.test.tld "ERR_CONNECTION_REFUSED"

Whatever circuitous path Yoga and Acrylic are taking, the result is an ipv4 address is being given to Chrome. There's no ipv4 listener on the WSL2 side.

/dupe #4851 #5298

Similar #5844 (message), your options are: (a) get Chrome to point at ipv6 ::1 via your DNS scheme, or, (b) get apache2 to listen on ipv4.

Spiritually related #4592 (message), whether bouncing DNS queries off of two third-party Windows networking services is a good idea can be left to the beholder. For an alternate approach to accomplishing a similar end result, folks may want to consider avahi-daemon(8).

[ghost]

Hi! We've identified this issue as a duplicate of another one that already exists in this repository. This specific instance is being closed in favor of tracking the concern over on the referenced thread.

Thanks for your report!

[gmnowels]

I am not sure if this feature is documented or available in stable Windows OS versions. For my case, I have tried this in latest Windows Insider build and it works. Create a /etc/wsl.conf file in your preffered WSL-ed GNU/Linux distribution. Add the following two lines in that /etc/wsl.conf file.

[network]
hostname = HelloWorld

Change the host name as you want.

Need to restart to see the change. What this does is change the name /etc/hosts file; where as, changing in the host file does not persist. In this case the wsl.conf settings will not persist.