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How can I log in to the linux server without a password by setting ssh? I believe that many inexperienced people are at a loss about this, so this article summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

Rsa authentication login method

Make a key pair

Enter the following command under the client (local machine) terminal

Ssh-keygen-t [rsa | dsa]

Rsa and dsa represent different algorithms

For example:

Ssh-keygen-t rsa

Just enter all the time (no need to set the password)

A key file and a private key file id_rsa,id_rsa.pub will be generated (or id_dsa,id_dsa.pub if dsa is used)

The build location is under the / root/.ssh/ folder (I am using the root user, so under root, the generation process will prompt for the location of the file)

.ssh is a hidden folder to view using ls-a

Place the public key at the location specified by the server

Method 1. Copy directly

1. Copy the public key to the .ssh folder under the root user of the server (under the .ssh folder under the user who logs in)

Scp / root/.ssh/id_rsa.pub root@172.16.0.164:/root/.ssh/

2. Install the public key

Log in to the server cd / root/.ssh/

Cat id_rsa.pub > > authorized_keys

Method 2. Use ssh-copy-id command to copy (recommended)

An order goes directly to ok.

Ssh-copy-id root@172.16.0.164

Verification

If you don't have to enter a password, you will succeed, otherwise you will fail.

Ssh root@172.16.0.164

Matters needing attention

The above operation has been tested and there is no problem.

There will be differences between the version of linux and the users used.

If there is a problem, you can consider the following two points

1. File permissions of id_rsa.pub and authorized_keys

Chmod 600 authorized_keyschmod 700 ~ / .ssh

2. Configuration file of ssh

Vim / etc/ssh/sshd_config # enables RSA authentication, defaults to yes RSAAuthentication yes to enable public key authentication, and defaults to yes PubkeyAuthentication yes # root user ssh login PermitRootLogin yes

(I haven't modified any of these configurations. Mine is redhat7.2.)

Customize and write a simple shell script

Create a file under the commonly used folder

Touch 164.sh

Edit a file

File content ssh root@172.16.0.164

Vim 164.sh # add content ssh root@172.16.0.164 save exit: wq

Increase the execution rights of users

Chmod upright x 164.sh

It's better to use the tab key.

. / 164.sh

Expect command secret-free login method

You may feel the need to operate the server system is not good, of course, you can only operate locally.

You only need to operate locally to use the expect command, provided you have the command expect locally.

1. Create a file

Touch expectssh.sh

Add the following to change the user, ip, and password to your own

#! / usr/bin/expect-f set username root set hostname 172.16.0.164 set password 123456 spawn ssh $username@$hostname set timeout 1 expect {"yes/no" {send "yes\ r"; exp_continue}} expect "$username@$hostname's password:" send "$password\ r" interact

2. Add expectssh.sh execution permission

Chmod upright x expectssh.sh

3. Execute orders

Expect expectssh.sh, after reading the above, have you mastered how to log in to the linux server without a password by setting ssh? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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