Connecting from off campus
Contents
Connecting from off campus#
When connecting from off campus additional steps are required to enable you to connect as the University HPC systems are only reachable from within the University network.
In the following example code snippets we’ll be connecting with the username exuser
. When you come to log in to a system you’ll need to use your own university username in place of exuser
.
Connecting from Linux/MacOS systems#
Warning
As of July 2021 the University is using 2-factor authentication for password-based access to remote-access. You will need to make sure you have enrolled with Duo with your University account and will be required to use Duo to authenticate after submitting your password to remote-access.
In order to connect to ARC when you’re off campus you’ll need to do some extra configuration so that your SSH connection goes via our remote-access
server. The following steps outline how to setup this configuration:
Open a Terminal on your Linux/macOS machine
Create a directory called
.ssh
in your home directory (if one doesn’t already exist)$ mkdir ~/.ssh
Then open a text editor of your choice and create a file called
config
in your.ssh
directory# for instance use the simple nano text editor $ nano ~/.ssh/config
Within this file include the following contents where
exuser
is replaced by your university usernameHost *.leeds.ac.uk !remote-access.leeds.ac.uk ProxyJump exuser@remote-access.leeds.ac.uk User exuser
Old version of SSH
If you’re using an old version of OpenSSH, you may get an error:
Bad configuration option: ProxyJump
. In this case you’ll want to use this instead:Host *.leeds.ac.uk !remote-access.leeds.ac.uk ProxyCommand ssh -o PreferredAuthentications=keyboard-interactive -W %h:%p exuser@remote-access.leeds.ac.uk User exuser
Save this file and your configuration is all set up!
You should now run the normal SSH commands in the terminal specifying the host you wish to connect to.
# to connect to ARC4
$ ssh arc4.leeds.ac.uk
# to connect to ARC3
$ ssh arc3.leeds.ac.uk
You’ll be prompted to login to remote-access.leeds.ac.uk first and may be presented with an interactive login that looks like below:
$ ssh arc4.leeds.ac.uk
Password:
After entering your password carefully if it is correct you will receive the Duo 2 factor authentication prompt.
$ ssh arc4.leeds.ac.uk
Password:
Duo two-factor login for exuser@leeds.ac.uk
Enter a passcode or select one of the following options:
1. Duo Push to +XX XXXX XXXXXXX
2. SMS passcodes to +XX XXXX XXXXXX (next code starts with: 2)
Passcode or option (1-2):
Enter your prefered option and authenticate using Duo and you will be prompted to enter your password for ARC4.
$ ssh arc4.leeds.ac.uk
Password:
Duo two-factor login for exuser@leeds.ac.uk
Enter a passcode or select one of the following options:
1. Duo Push to +XX XXXX XXXXXX
2. SMS passcodes to +XX XXXX XXXXXX (next code starts with: 2)
Passcode or option (1-2): 1
exuser@arc4.leeds.ac.uk's password:
Again carefully enter your password and if you’ve entered it correctly you’ll see the ARC4 message of the day (shown below) and have successfully connected.
Advanced Research Computing Node 4 (arc4)
________________________________________________________________________
Information on using this facility may be obtained at the following URL:
http://www.arc.leeds.ac.uk
Please remember to acknowledge the use of ARC facilities in your
papers; details are on the website above.
________________________________________________________________________
[exuser@login1.arc4 ~]$
Connecting from Windows#
Connecting from Windows requires the installation of an SSH client. We recommend and support users using MobaXTerm, please consult the setup section about installing this application.
Connecting via MobaXTerm#
Warning
As of July 2021 the University is using 2-factor authentication for password-based access to remote-access. You will need to make sure you have enrolled with Duo with your University account and will be required to use Duo to authenticate after submitting your password to remote-access.
Once you have MobaXTerm downloaded you can connect to ARC via two mechanisms: using the builtin local terminal to connect using SSH commands; or creating an SSH session via the GUI.
Creating an SSH session#
You can create an SSH session to connect to ARC using the following steps:
1. Open the initial MobaXTerm Menu and select Session |
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2. In the Session Wizard Window select SSH |
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3. Input the basic setting details for SSH session: the host (address of ARC), the username (your university username) |
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4. Select the Network Settings tab within the Session Settings window |
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5. Click on the large button labelled “SSH gateway (jump host)” and input details for connecting to remote-access.leeds.ac.uk (Gateway SSH server) and specify your username |
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6. You will immediately be prompted for your password to connect to the remote-access server |
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7. You will immediately be prompted for to enter your Duo two-factor code which can be found on your Duo App |
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8. After it accepts your password it will request your password again, this time to log into ARC4 (This may not happen automatically and you may need to double click on session name that appears on the left hand User sessions section) |
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Note
For security placeholder characters will not appear as you type your password. Your keystrokes are recorded so please type carefully!
9. Once successful you will see the ARC4 message of the day and the ARC prompt |
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10. You can restart an existing session after it has closed by double-clicking the session under the User sessions folder on the left-hand panel of the main MobaXTerm menu |
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Using the MobaXTerm Terminal#
Alternatively, you can connect to ARC using the builtin Terminal within MobaXTerm and use the ssh
command.
Configuring MobaXTerm Terminal#
In order to successfully connect off-campus you are required to adjust some settings within MobaXTerm to create a persistent home directory and create a configuration file for SSH.
1. Open the initial MobaXTerm Menu and select Settings |
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2. Select the folder icon on the right-hand side of the Persistent home directory setting box |
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3. Select a folder location to use for your persistent home directory (this can be any writeable folder on your computer), here I am using my C:\User\university_username folder |
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4. This takes you back to the MobaXTerm Setting Menu, where you can now select OK |
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5. You will then be prompted to restart MobaXTerm so that the new settings are applied |
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6. When MobaXTerm restarts, select the Start Local Terminal option |
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7. This takes you to the MobaXTerm terminal view |
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8. Next create a folder called |
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Note
If this folder already exists you will get an error saying this file/folder already exists just skip to step 9
9. Then go to Tools > MobaTextEditor |
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10. Type the contents of the file as follows where |
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Host *.leeds.ac.uk !remote-access.leeds.ac.uk |
11. Once complete go to File > Save As |
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12. Select the |
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13. Name the file as |
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And now MobaXTerm should be configured so we can SSH to ARC using the MobaXTerm Terminal.
SSHing via the MobaXTerm Terminal#
We can use the MobaXTerm Terminal like a standard unix shell to navigate around our local computer and also to SSH onto remote hosts including ARC. In order to connect to ARC we need to make sure we have configured MobaXTerm as described in the above section
1. Within a local Terminal on MobaXTerm we use the |
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2. We are then prompted to submit our password to connect to |
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3. We are then prompted select how to receive a Duo 2 factor authentication prompt either via the app or as a text message. Select your preferred option and either approve the push or input a passcode that is sent to you via SMS |
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3. We are then prompted to submit our password to connect to |
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4. Once we have successfully submitted our passwords our prompt will change and the message of the day for ARC4 will be displayed |
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