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Serv-U SSH host key changes after upgrading to version 15.2.0 and up to 15.3.0
This article shows the procedure of restoring the old default SSH private key in Serv-U after upgrading to version 15.2.0 and above
First published date
7/28/2020 3:57 PM
Last published date
5/31/2022 5:16 PM
Overview
In Serv-U MFT version 15.2.0, we have released a new default SSL certificate since it is already expired. Along with it, we also replaced the SSH private key. After upgrading Serv-U to 15.2.0 or above versions, some users started to notice that the SSH fingerprint key has changed, and this change is very critical to some users, especially if they have a very secure environment that only allows connection to known trusted keys. This also affects users who are connecting to Serv-U through SFTP using an automated script or application since they need to cache the new SSH key in Serv-U. Users who are connecting to Serv-U through FTP clients such as Filezilla, WinSCP, or FTP Voyager will also receive a prompt asking them to 'trust' or 'cache' the new SSH host key.
Product section
Serv-U Managed File Transfer & Serv-U FTP Server
Resolution
Reminder:
In new version which is 15.3.1, old default SSH keys cannot be restored while in older version which is 15.3.0 to lower version, you can still restore the old default SSH keys. Due to security enhancements, old default ssh keys will no longer work. Moving forward, we recommend to create your own SSH Keys to avoid this issue in the future upgrades.
1. Copy the two files from the old version of Serv-U installation folder C:\Program Files\RhinoSoft\Serv-U.
Serv-U-DefaultCertificate.crt
Serv-U-DefaultCertificate.key
2. Restore to the same installation path of the Serv-U server. There is no need to restart the Serv-U service after restoring the old files.
3. If the admin does not have a backup of the old Serv-U installation, another option would be installing the older version on another server temporarily then copy the files from step 1, or reach out to Serv-U support to get a copy of the files.
In new version which is 15.3.1, old default SSH keys cannot be restored while in older version which is 15.3.0 to lower version, you can still restore the old default SSH keys. Due to security enhancements, old default ssh keys will no longer work. Moving forward, we recommend to create your own SSH Keys to avoid this issue in the future upgrades.
1. Copy the two files from the old version of Serv-U installation folder C:\Program Files\RhinoSoft\Serv-U.
Serv-U-DefaultCertificate.crt
Serv-U-DefaultCertificate.key
2. Restore to the same installation path of the Serv-U server. There is no need to restart the Serv-U service after restoring the old files.
3. If the admin does not have a backup of the old Serv-U installation, another option would be installing the older version on another server temporarily then copy the files from step 1, or reach out to Serv-U support to get a copy of the files.