A.2. Graphical Access using X11

A.2. Graphical Access using X11
	Appendix A. Remote Access for the CCA Environment

Your remote CCA environment will be on a Linux(-like) system (because at present, the CCA tools do not run directly on Windows), in which graphical tools (such as text editors, debuggers, performance tools, etc.) typically use the X11 environment. If you wish to use these graphical tools remotely, you'll need an X11 environment on your local system. This is standard on most Linux(-like) systems. On Windows, you will probably have to install an X11 server.

	Warning
	Running X11 tools remotely can be annoyingly slow, especially over a long-haul connection or a slow network. You may prefer to stick to commandline tools.

Most SSH clients are capable of forwarding X11 traffic through your SSH session. If this option is available to you, it is probably the most convenient and definitely the most secure way of running X11 tools remotely. (It is possible for the administrator of the remote system to configure the SSH server to prevent X11 forwarding, but we try to insure that this is not the case on the systems we use for organized tutorials.)

A.2.1. OpenSSH

In most cases, SSH will forward X11 traffic by default, so the simplest thing is to go ahead and try it. To explicitly enable X11 forwarding use the -X option to ssh. If you want to disable it for some reason (for instance, it is too slow for your taste and you have a tendency to inadvertently start up graphical tools instead of commandline ones), then use the -x option.

A.2.2. PuTTY

In PuTTY, there is a checkbox to Enable X11 forwarding on the Connection → SSH → Tunnels configuration page.


Appendix A. Remote Access for the CCA Environment		A.3. Tunneling other Connections through SSH