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# Validate sshd changes without restarting the daemon
- URL: https://www.binarysludge.com/2015/02/12/validate-sshd-changes-without-restarting-the-daemon/
- Published: 2015-02-12T14:51:00.000Z
- Updated: 2016-10-02T18:23:04.000Z
- Author: Andrew Martin
- Tags: linux, System Administration, security, #Import 2026-10-22 12:56

The `-t` flag tests a configuration file *without restarting the `sshd` daemon*. This is helpful if you are `ssh`\-ed into a server and need to change the `sshd_config` file before updating your configuration management scripts - an error may prevent your server from accepting your next `ssh` session, or kick you off the box.

The `-f` option allows you to specify a file. Excluding it tests the current configuration file (i.e .`/etc/ssh/sshd_config`).

```
$ sudo sshd -t -f /tmp/sshd_config

```

This command can also be used to test for installed ciphers when changing cryptographic options, as well as syntax errors.