FastX Linux Client on Ubuntu/Debian Systems

The FastX Linux Client assumes that the SSH_ASKPASS environment variable is set in your desktop.  This is the case for many linux installations (RHEL/CentOs etc).  However, a default installation of Ubuntu does not set the SSH_ASKPASS environment variable even if it is installed.

Instead, users must set askpass themselves

sudo apt-get install ssh-askpass

Then run:
SSH_ASKPASS=/usr/bin/ssh-askpass /path/to/your/fastx2_client

You could then alias fastx2 in his .bashrc to launch that instead