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Help:Access to Cloud VPS instances with PuTTY and WinSCP

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This method is for older versions of the Windows operating system
The following information is the best option if you use Windows of an earlier version than Windows 10, April 2018 release.
If you are using a more recent version of Windows 10, your user experience use the built-in OpenSSH client, which also includes scp, by following the documentation at Help:Accessing Cloud VPS instances

This page documents methods for accessing your Cloud VPS instances using PuTTY and WinSCP.

  • PuTTY is a terminal emulator that has SSH support.
  • WinSCP is a Windows GUI for secure file transfer that has SFTP support.

There are extra instructions for accessing Toolforge with them.

With appropriate proxy respectively tunnel settings via the bastion server. With the correct settings,

Prerequisites

  • username: your shell username on Cloud Services, Gerrit, bastion and your instance (you may find it at Special:Preferences)
  • instance: your instance name like in the server name instance.eqiad1.wikimedia.cloud, e.g. openid-wiki.eqiad1.wikimedia.cloud
Important:
Please ensure you have the latest versions of each software installed. There have been reports of old versions not being able to establish connections to newer bastion hosts.
  • PuTTY
  • plink.exe (part of PuTTY suite)
  • Pageant (PuTTY authentication agent)
  • your generated and loaded-in-Pageant ssh key
  • WinSCP

See reference section for further information about tunnels and proxies.

How to set up PuTTY for proxying through bastion.wmcloud.org to your instance

The following screenshots may be out of date.

Important:
You have to manually make your first connection from bastion to your instance (i.e. not using the methods on this page). This in order to see and accept the server fingerprint!

Rationale: The first connection to an SSH server requires verification of the host key. PuTTY and also WinSCP store accepted server keys, and will alert you, if they differ later.[1]


The following uses an intermediate local proxy, part of the PuTTY suite.[2] 

plink.exe bastion.wmcloud.org -l <username> -agent -nc %host:%port

Hint: Make sure the proxy server (here: bastion) is already known to Putty before using it as a proxy. Otherwise you might just get a blank screen. If you are still getting the blank screen, you can run the plink command written above from the shell command line and accept the fingerprint. Then connect again with PuTTY as described above. Note that the proxied connection takes longer to establish than regular one (ie. you can wait 5 sec to get the remote prompt).

How to set up WinSCP for tunneling through bastion.wmcloud.org to your instance

Setting up WinSCP is very easy compared to setting up PuTTY.




Troubleshooting

SSH2_MSG_UNIMPLEMENTED

If you receive an error message similar to "Disconnected: Server protocol violation: unexpected SSH2_MSG_UNIMPLEMENTED packet", upgrade your PuTTY and plink.exe to a newer version. Older versions of PuTTY try to use encryption algorithms (ciphers) that are not supported by newer verisons of openssh.

Also ensure that in Connection->SSH->Kex section you have Diffie-Hellman group 14 set as the very first on the list "Algorithm selection policy".

References

  1. ↑ http://winscp.net/eng/docs/ssh#verifying_the_host_key
  2. ↑ Multihop SSH with Putty/WinSCP 01/09/2008 by Mike Lococo

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Read the Cloud Services Blog (for the broader Wikimedia movement, see the Wikimedia Technical Blog)

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