Difference between revisions of "SSH without password"
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First log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase: | First log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase: | ||
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a@A:~> ssh-keygen -t rsa | a@A:~> ssh-keygen -t rsa | ||
Generating public/private rsa key pair. | Generating public/private rsa key pair. | ||
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The key fingerprint is: | The key fingerprint is: | ||
3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A | 3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A | ||
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Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine): | Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine): | ||
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a@A:~> ssh b@B mkdir -p .ssh | a@A:~> ssh b@B mkdir -p .ssh | ||
b@B's password: | b@B's password: | ||
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Finally append a's new public key to b@B:.ssh/authorized_keys and enter b's password one last time: | Finally append a's new public key to b@B:.ssh/authorized_keys and enter b's password one last time: | ||
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a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys' | a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys' | ||
b@B's password: | b@B's password: | ||
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Revision as of 14:01, 22 January 2023
Your aim
You want to use Linux and OpenSSH to automize your tasks. Therefore you need an automatic login from host A / user a to Host B / user b. You don't want to enter any passwords, because you want to call ssh from a within a shell script. How to do it
First log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase:
a@A:~> ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/home/a/.ssh/id_rsa): Created directory '/home/a/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/a/.ssh/id_rsa. Your public key has been saved in /home/a/.ssh/id_rsa.pub. The key fingerprint is: 3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A
Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine): a@A:~> ssh b@B mkdir -p .ssh b@B's password:
Finally append a's new public key to b@B:.ssh/authorized_keys and enter b's password one last time:
a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys' b@B's password:
If you run ssh on a different port, add it to the ~/.ssh/config file
Host *
AddKeysToAgent yes UseKeychain yes IdentityFile ~/.ssh/id_ed25519 Port 2046
From now on you can log into B as b from A as a without password:
