sshd 命令

常用示例

说明

sshd is the OpenSSH server daemon that listens for incoming SSH connections, authenticates users, and provides encrypted remote shell access, file transfer, and port forwarding services. It is the server-side counterpart to the ssh client. The daemon supports multiple authentication methods including public key, password, keyboard-interactive, and GSSAPI/Kerberos. Access can be restricted by user, group, and source address through configuration directives. Features like X11 forwarding, agent forwarding, and TCP port forwarding are individually controllable. Debug mode (-d) runs a single connection in the foreground with verbose output for troubleshooting, while -t validates the configuration file for syntax errors before restarting the service. Foreground mode (-D) is commonly used in container environments where the daemon should not detach from the controlling process.

参数

-D

Run in foreground, do not daemonize

-d

Debug mode; process one connection with verbose output. Multiple -d increases verbosity (max 3).

-t

Test mode; validate configuration file syntax

-T

Extended test mode; output effective configuration to stdout

-C _connection_spec_

Specify connection parameters for -T match testing (user, host, addr, laddr, lport, rdomain)

-f _file_

Specify configuration file (default: /etc/ssh/sshd_config)

-h _host_key_file_

Specify host key file (can be given multiple times for different key types)

-g _login_grace_time_

Grace time for client authentication (default: 120 seconds)

-p _port_

Listen port (can be given multiple times)

-o _option_

Specify configuration options in key=value format

-E _log_file_

Append debug logs to log_file instead of system log

-e

Write debug logs to stderr instead of system log

-q

Quiet mode; suppress non-fatal log messages

-4

Force IPv4 addresses only

-6

Force IPv6 addresses only