Linux rookie starter process and knowledge about SSH

Openssh-server

Pstree View Initialization

Systemctl

Review and management of processes

1.systemd

System Initialization program, the first process started by the system,pid=1

2.systemctl command

Systenctl list-units List The status of the current system service

Systenctl List-unit-files lists the service's boot status

Systenctl status sshd View the state of the specified service

Systenctl stop sshd shuts down the specified service

Systenctl start sshd to start the specified service

Restart

Systenctl enable sshd to set the specified service to start

Systenctl Disable sshd settings specify service shutdown

Systenctl Reload SSHD enables the specified service to reload the configuration

Systenctl list-dependencies sshd View dependent relationships for specified services

Systenctl Mask sshd freezes the specified service

Systenctl unmask sshd Enable service

3. Service status.

Systemctl Status Service Mingcheng

The loaded system service has been initialized, loaded with

Active (running) service is being exploited by the system

The active (exited) service has already loaded the configuration, waiting for the system to exploit

Learning of Openssh-server Services

1.openssh-server

function: Allow remote host to access SSHD service over the network, start a secure shell

rm-fr/root/.ssh/

2. Client connection mode.

SSH remote host user @ remote host IP

Need to establish authentication relationship when connecting unfamiliar host

Remote user Password

SSH remote host user @ remote host Ip-x

Commond

3.sshkey encryption

①. Generating the public key private key

Ssh-keygen

Ls/root/.ssh

Id_rsa

Id_rsa.pub

②. Adding key authentication Methods

Ssh-copy-id-i/root/.ssh/id_rsa.pub [email protected]

③. Distributing keys

Scp/root/.ssh/id_rsa Root:/root/.ssh

④. Testing

4. Improve the OpenSSH security level

Openssh-server configuration file

/etc/ssh/sshd_config

78 Line setting Change to No: password logon is not allowed for improved security

Sysemctl Restart Sshd.service

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Linux rookie starter process and knowledge about SSH