userauth_pubkey: key type ssh-rsa not in PubkeyAcceptedAlgorithms
When login to an Ubuntu 22.04 server using FileZilla SFTP, got login failed error.
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Status: Connecting to 51.38.246.115:3333... Response: fzSftp started, protocol_version=9 Command: keyfile "/home/boby/.ssh/id_rsa" Command: Trust new Hostkey: Once Command: Pass: Error: Authentication failed. Error: Critical error: Could not connect to server Status: Disconnected from server |
On checking /var/log/auth.log, found the following error message.
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sshd[8916]: userauth_pubkey: key type ssh-rsa not in PubkeyAcceptedAlgorithms [preauth] sshd[8916]: Connection closed by authenticating user root MY_IP_ADDR port 56559 [preauth] |
The error “ssh-rsa not in PubkeyAcceptedAlgorithms” happens when trying to connect to a server which only support more secure algorithm, such as SHA-256 or better.
To fix the error, edit file
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vi /etc/ssh/sshd_config |
At the end of the file, add
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PubkeyAcceptedAlgorithms +ssh-rsa |
Restart sshd
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systemctl restart sshd |
To view currently supported Algorithms, run
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sshd -T | grep -i pubkeyacceptedkeytypes |
You can use pubkeyacceptedkeytypes instead of PubkeyAcceptedAlgorithms in /etc/ssh/sshd_config
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