HP ProCurve - Spheron1 https://www.spheron1.uk Thu, 07 Mar 2024 11:47:50 +0000 en-GB hourly 1 https://wordpress.org/?v=7.0.3 ProCurve SSH – no matching cipher found https://www.spheron1.uk/2018/09/24/procurve-ssh-no-matching-cipher-found/ https://www.spheron1.uk/2018/09/24/procurve-ssh-no-matching-cipher-found/#respond Mon, 24 Sep 2018 10:48:09 +0000 https://www.spheron1.uk/?p=971 I recently ran into a strange problem where I suddenly couldn’t SSH to any of our HPE ProCurve 2800 series (2824, 2848) devices from either macOS or Linux. I’m still not really sure what started this as OpenSSH definitely hasn’t been updated recently on the Linux client device at the very least, so I don’t see any reason for the...

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]]> I recently ran into a strange problem where I suddenly couldn’t SSH to any of our HPE ProCurve 2800 series (2824, 2848) devices from either macOS or Linux. I’m still not really sure what started this as OpenSSH definitely hasn’t been updated recently on the Linux client device at the very least, so I don’t see any reason for the list of ciphers supported on the client to have changed.

Anyway, the error message given by the OpenSSH client was:

Unable to negotiate with port 22: no matching cipher found. Their offer: des,3des-cbc

These ProCurves are pretty old and their SSH support is rather limited (1024 bit keys for example), so it’s not hugely surprising that their supported ciphers are also old and crappy.
Luckily, with OpenSSH you can specify the cipher(s) that you want to use on the command line when you’re connecting:

ssh -c 3des-cbc

This fixed the issue and lets me connect, but isn’t particularly convenient. However, you can also specify this in your ~/.ssh/config file so that it is applied automatically:

Host <blah>
Ciphers 3des-cbc

Just enter one or more hosts to match against (separated by spaces) and OpenSSH will automatically apply the specified options when connecting to any of them.

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]]> https://www.spheron1.uk/2018/09/24/procurve-ssh-no-matching-cipher-found/feed/ 0 SSH on a HP ProCurve https://www.spheron1.uk/2010/07/04/ssh-on-a-hp-procurve/ https://www.spheron1.uk/2010/07/04/ssh-on-a-hp-procurve/#respond Sun, 04 Jul 2010 15:32:15 +0000 https://www.spheron1.uk/?p=230 By default HP ProCurve devices (like most switches) use telnet and TFTP (Trivial File Transfer Protocol) for management access, firmware upgrades and config backups. As these are both unencrypted protocols, it is a good idea to switch to using SSH and SCP/SFTP in order to secure your management access and all important configuration, which you can do with the following...

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]]> By default HP ProCurve devices (like most switches) use telnet and TFTP (Trivial File Transfer Protocol) for management access, firmware upgrades and config backups. As these are both unencrypted protocols, it is a good idea to switch to using SSH and SCP/SFTP in order to secure your management access and all important configuration, which you can do with the following commands from configure mode:

crypto key generate ssh
ip ssh
ip ssh version 2
ip ssh filetransfer

This generates the keys that SSH requires, forces SSH to use the newer version two of the protocol and enables SCP/SFTP support for copying files to and from the flash.

As soon as you enable SSH filetransfer (basically SCP/SFTP) support then TFTP is disabled, but you have to disable telnet access manually in configuration mode with:

no telnet-server

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