How to access the HEP linux systems from MWS computers

This guide shows how to access the HEP computers from any of the MWS machines provided by the University.

ssh: Secure Shell, recommended for Linux and OSX systems

The machines can be accessed by the ssh command. This provides a text console and can also be used for graphics with additional software. This is the best solution when connecting from OSX or Linux machines.

ssh -l userid gateway.ph.liv.ac.uk

on another linux machine will ask to log the user userid onto the only system accessible from the outside of the group. The from gateway run

ssh iota

to connect to the iota machine in the cluster room.

If you are running a linux or OSX machine or cygwin on a windows machine then adding the -Y option will make graphics work as well.

ssh -Y -l userid gateway.ph.liv.ac.uk

you can test this by running a test command, for example xfontsel on the machine you connected to. When you connect from gateway to iota also add the -Y.

ssh on MWS

If it is not already installed run the Install University Applications command on the MWS machine and install PuTTy (version 0.6 at time of writing). This provides a windows implementation of ssh.

VNC, recommended for Windows computers and slower links (off campus)

VNC is open source software that send the display of one computer to another and send the keyboard and mouse inputs the other way. This software can connect to Linux machines or to Windows or OSX systems also, however you must first create the VNC listener on the system before you can connect.

VNC on MWS

While all MWS machines have a VNC installed (see the eye in the blue box in the system tray) it is easier to install TightVNC and use the view part of that.

However the vnclistener must have been started (only once is required) through ssh (see above).

To start a vnc session on a linux desktop just run, at a command prompt: vncserver

The first time you run this it should prompt you to set a password. You can run man vncserver to see additional options.

Vnc can run multiple displays on a single system, and these correspond to the ports it uses. So display :0 listens on port 5900, display :1 listens on port 5901, :2 on 5902, and so on. When you start the server it will tell you which vnc display it is (by default it uses the next available display, you can also specify a display when you start it). You need to know this to tunnel to it with SSH.

Now set the tunneling to the vncserver:

• Launch Putty. Different categories will be listed on the left side, click on Connection > SSH > Tunnels.
• Under Add new forwarded port:, enter the following information:
  • Source port: 5901
  • Destination: iota.hep.ph.liv.ac.uk:5901
  • Leave Local and Auto set
  • Click Add.
• Then in the same PuTTy session connect to the host (iota) running vncserver, leave this running
• Run TightVNC viewer and connect to localhost::5901 and use the same password you set up when running vncserver the first time
• Quite TightVNC viewer and PuTTy, but you can reconnect where you left off in the future from any MWS machine

Allow everyone to change this page:

• Set ALLOWTOPICCHANGE = LiverpoolHEPGroup

-- DavidHutchcroft - 21 Oct 2014