SecureShell - Revision history

Mbaney at 14:59, 10 April 2026

2026-04-10T14:59:25Z

← Older revision		Revision as of 14:59, 10 April 2026
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	This will give you access to a terminal on any one of the [[Nexus]] servers. Note that by default you will not have access to applications that require X11 to run.		This will give you access to a terminal on any one of the [[Nexus]] servers. Note that by default you will not have access to applications that require X11 to run.

	All UMIACS-supported Windows hosts are installed with [http://www.chiark.greenend.org.uk/~sgtatham/putty/ PuTTY]. If you are using a ~~self-supported~~ machine, you can either download and install PuTTY yourself, or if you are running a [https://docs.microsoft.com/en-us/lifecycle/products/windows-10-enterprise-and-education currently supported version of Windows], you can install the OpenSSH client natively in Windows by following Microsoft's instructions [https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_install_firstuse here]. Only the client is needed and not the server.		All UMIACS-supported Windows hosts are installed with [http://www.chiark.greenend.org.uk/~sgtatham/putty/ PuTTY]. If you are using a personal machine, you can either download and install PuTTY yourself, or if you are running a [https://docs.microsoft.com/en-us/lifecycle/products/windows-10-enterprise-and-education currently supported version of Windows], you can install the OpenSSH client natively in Windows by following Microsoft's instructions [https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_install_firstuse here]. Only the client is needed and not the server.

	==X11 Forwarding==		==X11 Forwarding==

Vsammeta: added alt text to images

2026-03-23T17:49:41Z

added alt text to images

← Older revision		Revision as of 17:49, 23 March 2026
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	If using PuTTY, you will need to enable X forwarding. The option is under Connection > SSH > X11, shown below.		If using PuTTY, you will need to enable X forwarding. The option is under Connection > SSH > X11, shown below.

	[[Image:Putty-x-forwarding.png]]		[[Image:Putty-x-forwarding.png \|alt=Enabling X11 Forwarding in PuTTY settings]]

	If using the [https://learn.microsoft.com/en-us/windows/terminal/install Windows Terminal app], you will need to set an environment variable and then relaunch the app.		If using the [https://learn.microsoft.com/en-us/windows/terminal/install Windows Terminal app], you will need to set an environment variable and then relaunch the app.
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	If you use PuTTY to connect to remote hosts, the prompt will be similar to the following:		If you use PuTTY to connect to remote hosts, the prompt will be similar to the following:

	[[File:Putty ssh host key prompt.png]]		[[File:Putty ssh host key prompt.png \|alt=PuTTY SSH host key prompt]]

	If the host key reported by PuTTY matches the [https://gitlab.umiacs.umd.edu/staff/ssh-fingerprints/blob/master/fingerprints Documented entry for that host], it is safe to click 'yes'. If you notice a discrepancy, please [[HelpDesk \| contact staff]].		If the host key reported by PuTTY matches the [https://gitlab.umiacs.umd.edu/staff/ssh-fingerprints/blob/master/fingerprints Documented entry for that host], it is safe to click 'yes'. If you notice a discrepancy, please [[HelpDesk \| contact staff]].

Mbaney at 20:35, 11 September 2025

2025-09-11T20:35:50Z

← Older revision		Revision as of 20:35, 11 September 2025
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	==Connecting to an SSH Server==		==Connecting to an SSH Server==
	Under Linux and macOS, the following command from a terminal will connect a client computer to the UMIACS [[Nexus]].		Under Linux and macOS, the following command from a terminal will connect a client computer to the UMIACS [[Nexus]].
	# ssh username@~~nexusgroup00~~.umiacs.umd.edu		# ssh username@nexusgroup.umiacs.umd.edu
	'''Note: Your Nexus submission node will vary depending on your sponsorship. See [[Nexus#Access\|Nexus Access]] for more information.'''		'''Note: Your Nexus submission node will vary depending on your sponsorship. See [[Nexus#Access\|Nexus Access]] for more information.'''
	This will give you access to a terminal on any one of the [[Nexus]] servers. Note that by default you will not have access to applications that require X11 to run.		This will give you access to a terminal on any one of the [[Nexus]] servers. Note that by default you will not have access to applications that require X11 to run.
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	Under Linux and macOS, the following command from a terminal will connect a client computer to the UMIACS [[Nexus]] using X11 Forwarding. Please note that under macOS, [http://xquartz.macosforge.org/landing/ xQuartz] is required on the client machine to forward X sessions from the remote session.		Under Linux and macOS, the following command from a terminal will connect a client computer to the UMIACS [[Nexus]] using X11 Forwarding. Please note that under macOS, [http://xquartz.macosforge.org/landing/ xQuartz] is required on the client machine to forward X sessions from the remote session.
	# ssh '''-Y''' username@~~nexusgroup00~~.umiacs.umd.edu		# ssh '''-Y''' username@nexusgroup.umiacs.umd.edu
	'''Note: Your Nexus submission node will vary depending on your sponsorship. See [[Nexus#Access\|Nexus Access]] for more information.'''		'''Note: Your Nexus submission node will vary depending on your sponsorship. See [[Nexus#Access\|Nexus Access]] for more information.'''

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	When connecting to a remove host for the first time, or when the remote host's local host key configuration has changed, you may see the following prompt:		When connecting to a remove host for the first time, or when the remote host's local host key configuration has changed, you may see the following prompt:
	<pre>		<pre>
	$ ssh username@~~nexusgroup00~~.umiacs.umd.edu		$ ssh username@nexusgroup.umiacs.umd.edu
	The authenticity of host '~~nexusgroup00~~.umiacs.umd.edu (128.8.121.73)' can't be established.		The authenticity of host 'nexusgroup.umiacs.umd.edu (128.8.121.73)' can't be established.
	RSA key fingerprint is 25:83:aa:df:f5:ad:5f:08:c9:8a:a3:5d:97:8b:48:1f.		RSA key fingerprint is 25:83:aa:df:f5:ad:5f:08:c9:8a:a3:5d:97:8b:48:1f.
	Are you sure you want to continue connecting (yes/no)?		Are you sure you want to continue connecting (yes/no)?
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	<pre>		<pre>
	$ ssh-keyscan -t rsa ~~nexusgroup00~~.umiacs.umd.edu > key		$ ssh-keyscan -t rsa nexusgroup.umiacs.umd.edu > key
	# ~~nexusgroup00~~.umiacs.umd.edu:22 SSH-2.0-OpenSSH_8.0		# nexusgroup.umiacs.umd.edu:22 SSH-2.0-OpenSSH_8.0
	$ ssh-keygen -l -E md5 -f key		$ ssh-keygen -l -E md5 -f key
	2048 MD5:25:83:aa:df:f5:ad:5f:08:c9:8a:a3:5d:97:8b:48:1f ~~nexusgroup00~~.umiacs.umd.edu (RSA)		2048 MD5:25:83:aa:df:f5:ad:5f:08:c9:8a:a3:5d:97:8b:48:1f nexusgroup.umiacs.umd.edu (RSA)
	</pre>		</pre>

Mbaney: /* SSH Keys (and Passwordless SSH) */

2025-03-21T14:35:25Z

SSH Keys (and Passwordless SSH)

← Older revision		Revision as of 14:35, 21 March 2025
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	Please see the [[SSH/Keys]] page for more information.		Please see the [[SSH/Keys]] page for more information.

	'''Note: UMIACS still requires multi-factor authentication if you are connecting from the public internet or a [[VPN]] for security reasons. SSH keys can only be used when connecting to a UMIACS-supported host from another UMIACS~~-supported host~~.'''		'''Note: UMIACS still requires multi-factor authentication if you are connecting from the public internet or a [[VPN]] for security reasons. SSH keys can only be used when connecting to a UMIACS-supported host from another host already within UMIACS' network border.'''

	==Verify remote host SSH fingerprint==		==Verify remote host SSH fingerprint==

Mbaney at 14:28, 21 March 2025

2025-03-21T14:28:31Z

← Older revision		Revision as of 14:28, 21 March 2025
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	Please see the [[SSH/Keys]] page for more information.		Please see the [[SSH/Keys]] page for more information.

	'''Note: UMIACS still requires multi-factor authentication if you are connecting from the public internet for security reasons.'''		'''Note: UMIACS still requires multi-factor authentication if you are connecting from the public internet or a [[VPN]] for security reasons. SSH keys can only be used when connecting to a UMIACS-supported host from another UMIACS-supported host.'''

	==Verify remote host SSH fingerprint==		==Verify remote host SSH fingerprint==

Mbaney at 15:52, 20 February 2025

2025-02-20T15:52:54Z

← Older revision		Revision as of 15:52, 20 February 2025
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	Please see the [[SSH/Keys]] page for more information.		Please see the [[SSH/Keys]] page for more information.

	'''Note: UMIACS still requires multi-factor authentication if you are connecting from the public internet for security reasons~~. If you first connect to our VPN, you should then be able to use the keys as normal~~.'''		'''Note: UMIACS still requires multi-factor authentication if you are connecting from the public internet for security reasons.'''

	==Verify remote host SSH fingerprint==		==Verify remote host SSH fingerprint==

Mbaney at 15:12, 30 January 2025

2025-01-30T15:12:26Z

← Older revision		Revision as of 15:12, 30 January 2025
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	[[File:Putty ssh host key prompt.png]]		[[File:Putty ssh host key prompt.png]]

	If the host key reported by PuTTY matches the [https://gitlab.umiacs.umd.edu/staff/ssh-fingerprints/blob/master/fingerprints Documented entry for that host], it is safe to click 'yes'. If ~~they do not match~~, please ~~report the issue to~~ [~~mailto:staff@umiacs.umd.edu~~ staff~~@umiacs.umd.edu~~].		If the host key reported by PuTTY matches the [https://gitlab.umiacs.umd.edu/staff/ssh-fingerprints/blob/master/fingerprints Documented entry for that host], it is safe to click 'yes'. If you notice a discrepancy, please [[HelpDesk \| contact staff]].

	===Other Platforms===		===Other Platforms===

Mbaney at 13:02, 23 September 2024

2024-09-23T13:02:58Z

← Older revision		Revision as of 13:02, 23 September 2024
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	After this has been done, every time you want to use X forwarding, you need to make sure VcXsrv or your other application has been started. If using VcXsrv, there will be an icon in your system tray.		After this has been done, every time you want to use X forwarding, you need to make sure VcXsrv or your other application has been started. If using VcXsrv, there will be an icon in your system tray.

	~~Now, you~~ will be able to use Xwindow programs from your ~~ssh~~ client.		You will now be able to use Xwindow programs from your SSH client.

	==SSH Tunneling==		==SSH Tunneling==

Jishjesu: /* SSH Keys (and Passwordless SSH) */

2023-11-06T20:16:31Z

SSH Keys (and Passwordless SSH)

← Older revision		Revision as of 20:16, 6 November 2023
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	Please see the [[SSH/Keys]] page for more information.		Please see the [[SSH/Keys]] page for more information.

	'''Note: UMIACS ~~would~~ still ~~require~~ multi-factor authentication if you are connecting from the public internet for security reasons. If you first connect to our VPN, you should then be able to use the keys as normal.'''		'''Note: UMIACS still requires multi-factor authentication if you are connecting from the public internet for security reasons. If you first connect to our VPN, you should then be able to use the keys as normal.'''

	==Verify remote host SSH fingerprint==		==Verify remote host SSH fingerprint==

Jishjesu: /* SSH Keys (and Passwordless SSH) */

2023-11-06T20:15:58Z

SSH Keys (and Passwordless SSH)

← Older revision		Revision as of 20:15, 6 November 2023
Line 38:		Line 38:

	Please see the [[SSH/Keys]] page for more information.		Please see the [[SSH/Keys]] page for more information.

			'''Note: UMIACS would still require multi-factor authentication if you are connecting from the public internet for security reasons. If you first connect to our VPN, you should then be able to use the keys as normal.'''

	==Verify remote host SSH fingerprint==		==Verify remote host SSH fingerprint==