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institute_lorentz:institutelorentz_remoteaccess [2016/08/12 10:09] – lenocil | institute_lorentz:institutelorentz_remoteaccess [2022/11/29 12:27] (current) – [SSH access/tunnelling behind firewalls] lenocil | ||
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====== Remote Access to your Workstation ====== | ====== Remote Access to your Workstation ====== | ||
- | For security reasons, access to your Lorentz workstation is only possible within the Lorentz | + | For security reasons, access to your Lorentz workstation is only possible within the Lorentz |
+ | |||
+ | Following are some examples that demonstrate the concept of SSH tunnelling. For alternative methods of connection, please see the relevant documentation. | ||
+ | SSH access to our servers requires you to set up [[institute_lorentz: | ||
+ | |||
+ | :!: The examples below have been tested with OpenSSH v7.3+. | ||
+ | |||
+ | ===== SSH tunneling ===== | ||
+ | By means of an SSH tunnel you can transport any arbitrary data over an encrypted SSH connection. Members of the Lorentz Institute can use | ||
+ | this technique to gain remote shell access to their workstation across our firewall which would prevent access otherwise. | ||
+ | |||
+ | ==== How does it work? ==== | ||
+ | |||
+ | |You must have an ssh client installed on your personal device -- e.g. laptop, PC -- in order to establish a // | ||
+ | |The Lorentz Institute has a dedicated server (SSH server) ready to listen to any (authenticated) client connections.| | ||
+ | |Once a client-server connection is established, | ||
+ | |The SSH client in turns forwards all encrypted application data to the server which finally communicates with the actual application server.| | ||
+ | |||
+ | For remote ssh connections to your IL workstation, | ||
+ | |||
+ | |||
+ | ==== Example 1 ==== | ||
+ | |||
+ | Establish an SSH connection to '' | ||
+ | |||
+ | <code bash> | ||
+ | ssh -o ProxyCommand=" | ||
+ | </ | ||
+ | |||
+ | :!: For connections that will use the DISPLAY environment variable (think of any application with a GUI), add the option '' | ||
+ | |||
+ | |||
+ | ==== Example 2 ==== | ||
+ | As in //Example 1// but this time using your client ssh configuration file usually located at '' | ||
- | Should you want to open an ssh session to your workstation and you are located outside the Lorentz network you can tunnel your request through '' | ||
< | < | ||
- | ssh -f < | + | # cat $HOME/.ssh/config |
+ | Host workstation.lorentz.leidenuniv.nl | ||
+ | | ||
+ | User username | ||
</ | </ | ||
- | instructs | + | |
- | ps aux | grep ss[h] | + | Once this configuration is in place, a simple '' |
- | your_username | + | |
+ | ==== Example 3 ==== | ||
+ | |||
+ | Establish a web browser connection | ||
+ | |||
+ | Configure your local '' | ||
+ | |||
+ | < | ||
+ | Host styx | ||
+ | HostName styx.lorentz.leidenuniv.nl | ||
+ | | ||
+ | |||
+ | Host workstation | ||
+ | | ||
+ | | ||
+ | | ||
</ | </ | ||
- | At this point you are ready to initiate an ssh session to your workstation | + | |
+ | Browse | ||
+ | |||
+ | |||
+ | ==== Example 4 ==== | ||
+ | Establish a web browser connection to a Jupyter Notebook | ||
< | < | ||
- | ssh -p 2222 localhost | + | Host lorentz |
+ | | ||
+ | User username | ||
+ | |||
+ | Host maris | ||
+ | | ||
+ | | ||
+ | User username | ||
+ | |||
+ | Host marisXX | ||
+ | | ||
+ | | ||
+ | User username | ||
+ | | ||
</ | </ | ||
- | NOTE: Should you want ssh to set the DISPLAY environment variable, you can use option | + | Browse |
+ | ===== SSH access/ | ||
- | ===== Another possible trick: ===== | + | There are situations in which SSH could be forbidden by firewall settings of the internet service provider. Think of countries which limit freedom of speech for example. Luckily Lorentz Institute provides its members with a special |
- | Locally (e.g. on your laptop), create a file '' | + | |
- | Host asselijn.lorentz.leidenuniv.nl asselijn | + | |
- | ProxyCommand / | + | |
- | And if you have a different username locally and on the institute desktops, that can be added like this: | + | |
- | Host asselijn.lorentz.leidenuniv.nl asselijn | + | |
- | ProxyCommand / | + | |
- | User username | + | |
- | If you need access to multiple hosts, just copy and edit this section. | + | |
- | --- | + | In a nutshell, IL offers SSL-wrapped SSH access, that is it conceals SSH connections using the SSL protocol which is the protocol used by the world wide web to serve '' |
- | ==== Using Putty ==== | + | The set up on your side is rather simple and requires only editing |
- | You will need to open two putty sessions. | + | |
- | === Session 1: Tunnel === | + | |
- | Open putty and create a session called Tunnel, then set it according to the snapshots below | + | |
- | {{ :institute_lorentz: | + | Add the following stanza to your SSH client config file((The same result is obtained by executing directly '' |
- | {{ : | + | <code bash> |
+ | Host ssh.lorentz.firewall | ||
+ | ProxyCommand openssl s_client -connect access.lorentz.leidenuniv.nl: | ||
+ | User <Your IL username> | ||
+ | </ | ||
+ | Then to initiate a SSL-wrapped SSH connection open a terminal and type | ||
+ | <code bash> | ||
+ | $ ssh ssh.lorentz.firewall | ||
+ | depth=2 C = US, ST = New Jersey, L = Jersey City, O = The USERTRUST Network, CN = USERTrust RSA Certification Authority | ||
+ | verify return:1 | ||
+ | depth=1 C = NL, O = GEANT Vereniging, CN = GEANT OV RSA CA 4 | ||
+ | verify return:1 | ||
+ | depth=0 C = NL, ST = Zuid-Holland, | ||
+ | verify return:1 | ||
- | Please note the settings in the port forwarding panel. We use an arbitrary port (2222), but you can choose any numbers above 1024 provided they are not currently in use. By pushing `Open', | + | -------------------------------------------------- |
- | with the creation of session `Tunnel_use' | + | Welcome to the Lorentz Institute workstations |
+ | Access is allowed for authorized users only. | ||
+ | Any abuse will be tracked. | ||
- | {{ : | + | Helpdesk |
+ | https:// | ||
+ | support@lorentz.leidenuniv.nl | ||
+ | -------------------------------------------------- | ||
+ | |||
+ | READ THIS CAREFULLY BEFORE PROCEEDING: | ||
+ | ------------------------------------- | ||
+ | https:// | ||
+ | |||
+ | Last login: Tue May 17 09:36:49 2022 from XX.XX.XX.XX | ||
+ | ***** | ||
+ | |||
+ | $ | ||
+ | </ | ||
+ | |||
+ | When the connection is initiated you will be able to double-check the SSL certificate details, especially the '' | ||
+ | |||
+ | Similarly it is possible to initiate an SSL-wrapped SSH SOCKS proxy connection useful to protect your browser sessions from eavesdroppers | ||
+ | |||
+ | <code bash> | ||
+ | ssh -ND 8888 ssh.lorentz.firewall | ||
+ | </ | ||
- | Now push `Open' and a terminal will appear asking your authentication credentials | + | then modify your browser settings to instruct it to redirect all connections to a SOCKS proxy listening |
- | ===== VNC: GNU/Linux ===== | + | |
- | For detailed instructions on how to set up a vnc session you are encouraged to follow [[: | + | |
- | ===== VNC: Windows Users ===== | + | |
- | Please read [[linux: | + | |