Remote Access in Theoretical Physics

There are several ways of accessing your system and data remotely on the Theoretical Physics systems.

How to access Theoretical Physics computers via SSH

Systems within the Physics network may be accessed via the ssh proxy server

On Mac or Linux, edit the file ~/.ssh/config and add the lines

Host * ForwardAgent no VisualHostKey yes HostKeyAlgorithms=ssh-ed25519 TcpKeepAlive yes ServerAliveInterval 60
Host User your_physics_username
Host tplxdt123 User your_physics_username Hostname ProxyJump

If you are running code then we strongly recommend that you use screen. This will allow you to disconnect and reconnect from both the remote system and the ssh gateway without stopping your code from running. Use ctrl-a ? for help, ctrl-a d to detach, "screen -x" to reattach, "screen" from within screen to create another screen, ctrl-a N where N = 0...9 to switch screens, ctrl-a F to resize to current terminal. For a quick reattach after a dropped internet link, use ssh -t tplxdt123 screen -x

Please Note: The first time that you ssh into either SSH gateway you will receive an error that your home directory isn't available. Ignore this message, the gateway home directory is mounted in /home/username.

The host key fingerprint is as below.

Host key fingerprint is SHA256:B3rVd78/alhgZUs3yt6gqPDLkhRFTqKtZhvvX1Y9gGk +--[ED25519 256]--+ | ..o | | o +. o. + o | | . ....E..* = o| | .. ..o oo* ..| | = o S +.+oo .| | o +o . o.. o...| | ...+ .o o . | | .o.oo . . ..| | .o+. ... o| +----[SHA256]-----+

(the ECDSA key is as below, which you may have previously stored in your ~/.ssh/known_hosts file)

Host key fingerprint is SHA256:7n9a7/YyMKWXWvHXYVTeMfbXp1Xblcjy8/s+6Mvytzk +---[ECDSA 256]---+ | . .+*| | . o.+@| | o ..X| | oo=o| | S o=+o| | . + +.+| | . .*. o| | . o+o+E.| | ..oo+B=BO| +----[SHA256]-----+

Note that this page may be accessed via SSL.

You can then ssh to your system with e.g.
ssh tplxdt123

to run graphical applications, use

ssh tplxdt123 -X

This is quite slow, however. If you need faster access, use x2goclient with as an ssh proxy (tick the box to enable that), and the same username and password boxes ticked. Set the session type to XFCE.

Troubleshooting ssh

If the second login hangs, try

ssh tplxdt123 -oPubkeyAuthentication=no

If you log in but cannot see your files, try kinit and enter your password.

Virtual Private Network (VPN)

A Virtual Private Network (VPN) is a way of extending our internal network out to systems connected on the internet. Once connected via a VPN, a remote system appears to be connected locally to our network thereby getting all the facilities available to local users and avoiding blocks placed in intervening firewalls. All data passed via a VPN is encrypted.

Instructions for setting up VPN can be found here.

Once you have established a VPN connection then you can ssh directly into your desktop system.

Virtual Network Computing to Apple desktops

VNC allows you to take control of the Graphical interface of your Apple desktop remotely. Instructions on how to setup VNC can be found here

Linux Remote desktop

The Linux interactive machines can be accessed via x2go (Download)
This can be set up on your Linux desktop by request. Set the ssh gateway to, use the same username and password. Set the session type to XFCE.

Categories: Remote Access | Theory