# How to fix “MobaXterm X11 proxy: Unsupported authorisation protocol”

mobaxtermx-serverx11-forwardingxauth

When connecting from Windows to my Linux box using MobaXterm, I cannot open Linux-GUI applications on the Windows side. On the Windows side, nothing happens. On the Linux box I get this error message:

MobaXterm X11 proxy: Unsupported authorisation protocol
** ([program]:[processId]): WARNING **: Could not open display localhost:10.0


In my case, the problem was a missing entry in ~/.Xautority on the Linux machine. You probably shouldn't edit the file directly, but use the commandline tool xauth.

Take the display name and the id from the error message and use them in the xauth command.

Could not open display localhost:10.0
 


In my case it's localhost and 10. To add it, use the xauth add command:

xauth add localhost/unix:10 MIT-MAGIC-COOKIE-1 27e035688dd89483c6fe48b2470172f5
      


The last hex-number is 32 characters long. You can create your own (quite) random number on the Linux shell with one of these commands:

mcookie

uuidgen -r | sed s/-//g

head -c 16 /dev/urandom | xxd -p


You can check, what has been added by command xauth list.