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DocumentationCloud Virtual MachineTroubleshootingInstance-Related FailuresLinux Instance Login Failuressshd Configuration File Permissions
sshd Configuration File Permissions
Last updated: 2024-01-06 17:32:18
Issue Description
During login to a Linux instance via SSH key, "ssh_exchange_identification: Connection closed by remote host" or "no hostkey alg" is displayed.
Common Causes
sshd configuration file permissions, such as the permissions of the
/var/empty/sshd or /etc/ssh/ssh_host_rsa_key configuration file, are modified, which may cause a failure in login via SSH key.Solution
Perform the steps based on the actual error message to modify the configuration file permissions:
If the error message is "ssh_exchange_identification: Connection closed by remote host", see Modifying permissions of
/var/empty/sshd file.If the error message is "no hostkey alg", see Modifying permissions of
/etc/ssh/ssh_host_rsa_key file.Troubleshooting Procedure
Modifying permissions of /var/empty/sshd file
2. Run the following command to view the error cause:
sshd -t
Information similar to the following is returned:
"/var/empty/sshd must be owned by root and not group or world-writable."
3. Run the following command to modify the permissions of the
/var/empty/sshd/ file:chmod 711 /var/empty/sshd/
Modifying permissions of /etc/ssh/ssh_host_rsa_key file
2. Run the following command to view the error cause:
sshd -t
The returned information contains the following field:
"/etc/ssh/ssh_host_rsa_key are too open"
3. Run the following command to modify the permissions of the
/etc/ssh/ssh_host_rsa_key file:chmod 600 /etc/ssh/ssh_host_rsa_key
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