Setting up debugging with XDebug 3 and WSL2

Tried the steps mentioned in this post and post. However, debugging continues to fail due to the following error: 

Connection was not established. Cannot start debugger session with 'Xdebug 3.0.4'

XDebug Config:



This is a portion of the command executed by PHPStorm when debugging:

Unsure as to why the remote_host is passed as

php -dxdebug.remote_enable=1 -dxdebug.remote_mode=req -dxdebug.remote_port=9000 -dxdebug.remote_host= "-d xdebug.remote_host=" "-d xdebug.client_host=" "-d xdebug.remote_port=9000" -dxdebug.client_port=9000


And this is a portion of the command executed by PHPStorm when running a script/test:

php "-d xdebug.remote_host=" "-d xdebug.client_host=" "-d xdebug.remote_port=9000" -dxdebug.client_port=9000

In this case PHPStorm does not automatically pass as remote_host's value and only the values setup in the XDebug options in IDE are passed.

Had uninstalled anti-virus and also disabled the firewall. However, debugging connection fails. Strangely nothing is written to xdebug logs.

System Info

PHPStorm Version: PhpStorm 2020.2.4
Build #PS-202.8194.11, built on November 25, 2020
Licensed to Nikhil Ranka
You have a perpetual fallback license for this version
Subscription is active until May 4, 2022
Runtime version: 11.0.9+11-b944.49 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Windows 10 10.0

Would be great if you could help in setting this up.


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First of all, you're running an old IDE version: 2020.2.4. A series of fixes were released since then both aiming at XDebug 3 & WSL configuration so I would suggest testing this on latest IDE version.

Next, please check if debugging works with "phone" button toggled to "listen":

Also: is your IDE installed on the Windows host or inside WSL?

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Ok, Dmitry Tronin thought so. Will update the IDE. Kept myself from updating because most features that I wanted were working as expected. Also noticed that in recent updates some required features were breaking. 

- The phone button is toggled to Listen.

- Using on WIndows. Any benefits to using the IDE on WSL? Would want to be able to run projects on both Windows and WSL. 


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Updated the IDE to the latest version 2021.2.2. The debugging now works. Had to additionally set the settings here:

Had not found this in the documentation. Probably my oversight or documentation does not have it. 

When the internet is turned off it stops working. Can you suggest a workaround for the same?



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Dmitry Tronin Any insights on the above?

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1) We don't have WSL-specific instructions for XDebug yet, unfortunately. The options you set in the Interpreter Configuration options could as well be set in a php.ini. Didn't that work for you initially?

2) Regarding the broken debug after turning off the internet. Looks like a firewall issue. Try granting PhpStorm an access at Control Panel\System and Security\Windows Defender Firewall\Allowed apps


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