Linux/X11 Forwarding

PuTTy and

VcXsrv Windows X Server
https://sourceforge.net/projects/vcxsrv/

21.1.10 latest as of 2024.01.07:
https://sourceforge.net/projects/vcxsrv/files/vcxsrv/21.1.10/

Local on system:

DISPLAY=localhost:0.0

Using Putty/Kitty with VcXsrv:

DISPLAY=localhost:10.0

Most simple X11 programs like xterm, xclock will just work with default settings. Some, like gvim, need this always redirect GL setting:

export LIBGL_ALWAYS_INDIRECT=1

PuTTy and Xming

Installing/Configuring PuTTy and Xming
https://www.geo.mtu.edu/geoschem/docs/putty_install.html

Firefox AppArmor

Some programs like Firefox just refuse to X11 forward, due to AppArmor restrictions. Tried killing AppArmor but it made the system sad, and Firefox then complained about not having AppArmor working. Sigh.

If you happen to try and remove Snap's Firefox on Ubuntu 22, trying to fix the AppArmor issue, you may get this:

sudo snap remove firefox
sudo apt install firefox

firefox &
 ...
 Command '/usr/bin/firefox' requires the firefox snap to be installed.
 Please install it with:
 snap install firefox

sudo snap install firefox
  snap "firefox" is already installed, see 'snap help refresh'

This worked to resolve it:

sudo apt remove --purge snapd
sudo umount /var/snap/firefox/common/host-hunspell
sudo apt remove --purge snapd
sudo apt install snapd
sudo snap install firefox