Secure Shell (SSH) is a cryptographic network protocol used for a secure connection between a client and a server and supports various authentication mechanisms.
How to set up ssh so you aren't asked for a password. On your machine, and just hit enter when asked for a password. This will generate both a private and a public key. With older SSH versions. It's possible to have the developer database propagate your key to all of the debian.org machines. Re: How do you manage your SSH host keys? Posted by Anonymous (166.84.xx.xx) on Tue 7 May 2013 at 14:06 Shouldn't SSH host key fingerprints be delivered by SSL or other secure medium? Jun 22, 2012 SSH keys provide a more secure way of logging into a server with SSH than using a password alone. While a password can eventually be cracked with a brute force attack, SSH keys are nearly impossible to decipher by brute force alone. Generating a key pair provides you with two long string of characters: a public and a private key. $ ssh-keygen -s cakey -I keyid -h -n host.domain userkey.pub Additional limitations on the validity and use of user certificates may be specified through certificate options. A certificate option may disable features of the SSH session, may be valid only when presented from particular source addresses or may force the use of a specific command. The remote SSH host key has been generated on a Debian or Ubuntu system which contains a bug in the random number generator of its OpenSSL library. The problem is due to a Debian packager removing nearly all sources of entropy in the remote version of OpenSSL.
The two most popular mechanisms are password based and public-key based authentication. Using SSH keys is more secure and convenient than traditional password authentication.
In this tutorial, we will describe how to generate SSH keys on Debian 9 systems. We will also show you how to set up an SSH key-based authentication and connect to your remote Linux servers without entering a password.
Creating SSH keys on Debian #
Before generating a new SSH key pair first, check for existing SSH keys on your Debian client machine. You can do that by running the following ls command:
If the output of the command above contains something like No such file or directory or no matches found it means that you don’t have SSH keys, and you can continue with the next step and generate a new SSH key pair.
If there are existing keys, you can either use those and skip the next step or backup up the old keys and generate new ones.
Start by generating a new 4096 bits SSH key pair with your email address as a comment using the following command:
The output will look similar to the following:
Press Enter to accept the default file location and file name.
Next, you’ll be prompted to type a secure passphrase. Whether you want to use passphrase, it’s up to you. With passphrase, an extra layer of security is added to your key.
If you don’t want to use passphrase just press Enter.
The program comes with an interface that’s simple and simple. It’s higher than 5 million users all over the universe. 
In to Windows or Mac systems, you can shuffle with this specific particular application program.Just by changing the windows port no requirement to reboot into the own procedure.
The whole interaction looks like this:
To verify that the SSH key pair was generated, type:
The output should look something like this:
Copy the Public Key to the Server #
Now that you have your SSH key pair, the next step is to copy the public key to the server you want to manage.
The easiest and the recommended way to copy the public key to the remote server is to use the ssh-copy-id tool.
On your local machine terminal run the following command:
You will be prompted to enter the remote_username password:
Debian Ssh Host Key Generation 2017
Once the user is authenticated, the public key ~/.ssh/id_rsa.pub will be appended to the remote user ~/.ssh/authorized_keys file, and connection will be closed.
If the ssh-copy-id utility is not available on your local computer, you can use the following command to copy the public key:
You can generate an SSH key on Windows using the. Putty generate ssh key lightsail and filezila.
Login to the Server using SSH Keys #
At this point, you should be able to log in to the remote server without being prompted for a password.
To test it, try to connect to the server via SSH:
If you haven’t set a passphrase, you will be logged in immediately. Otherwise, you will be prompted to enter the passphrase.
Disabling SSH Password Authentication #
To add an extra layer of security to your server, you can disable the password authentication for SSH.
Before disabling SSH password authentication, make sure you can log in to your server without a password, and the user you are logging in with has sudo privileges.
Log into your remote server:
Open the SSH configuration file /etc/ssh/sshd_config:
Search for the following directives and modify as it follows:
Once you are done, save the file and restart the SSH service using the following command:
At this point, the password-based authentication is disabled.
Conclusion #
Debian 9 Ssh
In this tutorial, you have learned how to generate a new SSH key pair and set up an SSH key-based authentication. You can add the same key to multiple remote servers.
We have also shown you how to disable SSH password authentication and add an extra layer of security to your server.
By default, SSH listens on port 22. Changing the default SSH port reduces the risk of automated attacks.
If you are regularly connecting to multiple systems, you can simplify your workflow by defining all of your connections in the SSH config file.
Ssh Host Key Generation
If you have any questions or feedback, feel free to leave a comment.