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Adrian (Softland)
Jul 06, 2022
Backup4all 9
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A cipher is an algorithm for performing encryption or decryption, a series of well-defined steps that can be followed as a procedure.
In Backup4all, ciphers are used for SFTP locations (source or destination) in case your SFTP server is installed on a Linux/Unix server.
Sometimes Backup4all gives you Unsupported cipher Connection lost error when it tries to connect to a Linux/Unix server. That means the ciphers needed by Backup4all are not enabled on that Linux/Unix server.
This article explains how to enable the necessarily ciphers on Linux.
Please follow these steps:

2. Login with Putty as root user

3. List ciphers enabled on your server:
ssh -Q ciphers
4. Enable the necessarily ciphers in sshd_config file:
nano /etc/ssh/sshd_config  
# or: mcedit /etc/ssh/sshd_config
Backup4all ciphers
5. Add these lines at the end of the sshd_config file:
Ciphers +aes256-ctr
MACs +hmac-sha1
6. Restart sshd service by running:
service sshd restart
Then try again to run the backup.