[LINUX] Ubuntu (18.04.3) SSH edition Key authentication

1. Update ``` $ ssh -p port number account [email protected] address ```

In the previous article, you can already enter from the Mac terminal.

$ sudo apt update

Every time. I will never forget this.

2. Creating a key (server side) As a key storage destination Create a key with /home/username/.ssh.
$ ssh-keygen -t rsa -f arbitrary name

Specify password.

Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 

Check below

$ ls

Any name: private key Any name.pub: Public key

3. Various settings (miscellaneous) ``` vi arbitrary name ``` This will copy the contents.

The rest is Mac /Users/username/.ssh/private key Copy the contents to and save.

Then do the following:

$cat arbitrary name.pub >> authorized_keys

Change permissions.

$ chmod 600 authorized_keys
$ chmod 700 /home/account name/.ssh

Delete original public key

rm -f arbitrary name.pub 

Delete private key

$rm any name

/etc/ssh/sshd_config Add (or uncomment) the following to.

+ChallengeResponseAuthentication no
+PubkeyAuthentication yes

sshd restart

$ sudo /etc/init.d/ssh restart

Create /Users/accountname/.ssh/config for Mac

Host account name
HostName IP address
User account name
        IdentityFile /Users/account name/.ssh/account name
Port Port number

with this,

$ssh account name

Put in

Password authentication is still possible at this point, so add (or uncomment) the following

+PasswordAuthentication no

Well then

$ssh account name
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
・ ・ ・ ・ ・ ・ ・ ・ ・

Oops ... It looks like you have to change the permissions on your Mac.

$ chmod 0600 ~/.ssh/

Then, once again.

Enter passphrase for key ‘・ ・ ・ ・ ・ ・

Now enter with the password you entered when creating the key.

By the way, it seems that the password for the ssh key cannot be saved with config.

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