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Test the sshd config and reload the SSH service

caution rootSSHdebian, ubuntu

Caution: This command changes the system. Understand what it does before you run it.

root@server
sshd -t && systemctl reload ssh

sshd -t checks the configuration, including included files from /etc/ssh/sshd_config.d/, and prints the offending line on errors. The service is only reloaded if the test succeeds. Existing sessions are kept.

Note: Keep the current session open and test the login in a second terminal. On Ubuntu 24.04, SSH is started via ssh.socket, so a port change there also requires systemctl daemon-reload and systemctl restart ssh.socket.

Also searched as

  • test sshd config before restart
  • sshd -t syntax check
  • reload ssh without losing connection

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