ssh keys with Openssh

ssh keys

From my laptop I will create the keys and I will expose this key to the server I want to connect using keys. Additionally we get rid of passwords , even for my user as sudo user.

jordi@LAPTOP-ELFAQNCG MINGW64 ~/.ssh

$ ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/c/Users/jordi/.ssh/id_rsa):

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /c/Users/jordi/.ssh/id_rsa.

Your public key has been saved in /c/Users/jordi/.ssh/id_rsa.pub.

The key fingerprint is:

SHA256:ljvEge2a/MwKp8OK73ai27v7zRFiPyPmMxJCpw0nJLU jordi@LAPTOP-ELFAQNCG

The key's randomart image is:

+---[RSA 2048]----+

| ..              |

|.. .   o         |

|o E   . o        |

| + o   o o       |

|. B o . S        |

|...o + * .       |

| . o+ X o        |

| o+o*B B .       |

|+*OX+++.+        |

+----[SHA256]-----+

jordi@LAPTOP-ELFAQNCG MINGW64 ~/.ssh

$ ssh-copy-id jordi@localhost

/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/c/Users/jordi/.ssh/id_rsa.pub"

/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed

/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys

no such identity: /c/Users/jordi/.ssh/keys/id_rsa.pub: No such file or directory

jordi@localhost's password:

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'jordi@localhost'"

and check to make sure that only the key(s) you wanted were added

jordi@LAPTOP-ELFAQNCG MINGW64 ~/.ssh

$ cat config

Host localhost

 Hostname localhost

 IdentityFile ~/.ssh/id_rsa

.

jordi@LAPTOP-ELFAQNCG MINGW64 ~/.ssh

$ ssh localhost

Last login: Sat Feb  3 17:27:47 2018 from gateway

[jordi@localhost ~]$

At centos to avoid password for instance to avoid pas to do sudo

/etc/ssh/sshd_config

PasswordAuthentication no

addl to the bototn

 sudo visudo

jordi ALL=(ALL) NOPASSWD: ALL