Linux generates public and private keys

Server A: 192.168.1.1

Server B: 192.168.1.2

Server A:

Configuration:

ssh-keygen -b 2048 -t rsa                    

#Here -b 2048 is the length of the key encryption, it is better to set it larger, it is reported that there are hackers in the United States to solve the ssh key to crack.
# http://bbs.yuloo.com/thread-860154-1-1.html

Enter directly 3 times

The key file will be saved in the /root/.ssh directory

At this time, there will be several more files in .ssh

id_rsa private key file

id_rsa.pub Public key file, the contents of this file should be placed in other hosts.

View the id_rsa.pub file

cat /roor/.ssh/id_rsa.pub

ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIcAvh6Lz9ghftghtfghSv + kSrxVLC9UDKq27mg5vhfghAaWcgFgllZhfg2DLnGotmeL / 08bp6jMW / ekSq1BY1eiouiluiliuliul2Rr84x0bB5YShhpgJwuPbwr / pymgukyukyukyuthjkiytiliunzdfkuykyuIZgVvgPTzNdN / RDwJMsafsdvgsdsfsdfdsfsdaflozStYcWjrwzYxsroDPBy4zjd0gH5zMYhj + + vS4OOAZZ8rtHEfx sTE0 =  [email protected]

Server B:

Configuration:

Create new folders and files

mkdir /root/.ssh

vim /root/.ssh/authorized_keys

Copy the contents of the KEY file viewed on server A to authorized_keys on server B

The main thing is to change [email protected] to [email protected]  so that it is convenient to check which server's KEY is, and there may be multiple servers' keys.

Modify the main configuration file of sshd, disable password authentication login, and use key to log in.

vim /etc/ssh/sshd_config

Find PasswordAuthentication yes 

Change to PasswordAuthentication no

service sshd restart

test:

Execute on server A

ssh [email protected] 

The first login will require you to enter YES. See if you can log in to the B service without a password.