SSH Key based authentication is very useful for transferring data and for some data sync applications to work, to configure the key based login on a CentOS Server
1. Generate SSH Key pair by running
[root@localhost ~]# ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa): Created directory '/root/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /root/.ssh/id_rsa. Your public key has been saved in /root/.ssh/id_rsa.pub. The key fingerprint is: 5b:9c:74:08:15:4a:13:13:cb:15:ff:c2:f6:d8:0b:d3 [email protected] The key's randomart image is: +--[ RSA 2048]----+ | B+=o | | o B o | | + o o | | o + . | | S + + . | | o . * | | . + E | | o . | | . | +-----------------+
Passphrase for the key is optional and you can leave it blank.
2. Once the key pair is generated copy it to the remote server using
[root@localhost ~]# ssh-copy-id -i /root/.ssh/<PUBFILE>.pub [email protected] The authenticity of host '192.168.1.2 (192.168.1.2)' can't be established. RSA key fingerprint is 5c:3a:99:15:46:a6:56:1c:66:5c:1e:ed:ea:76:a3:cd. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '192.168.1.2' (RSA) to the list of known hosts. [email protected]'s password:
3. Once the key is copied successfully, you can start logging into the server by just login using
4. If the other server is running SSH service on a different port other that the default (22) you need to copy the ssh key as below
ssh-copy-id -i /root/.ssh/<FILENAME>.pub "[email protected] -p 2232"