Can you set passwords in .ssh/config to allow automatic login?

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If you are accessing a remote server frequently, it is convenient for you to be able to SSH to the remote host without entering an SSH password. Passwordless SSH login is even more useful when you are using SSH for non-interactive purposes, for example, for filesystem mount, offsite backup, etc. Also, many distributed systems or cloud orchestration layers (e.g., OpenStack) leverage password-less SSH authentication to control remote compute nodes.

If you want to log in to a remote SSH server without entering an SSH password, you can instead use key-based authentication, where you install your public key on a remote server a priori, and then log in to the server non-interactively by presenting your private key as an authentication key.

Here is how to enable SSH login without entering an SSH password.

Assume that you are a user account alice on host1, and wish to ssh to host2 as user bob, without entering the bob's password.

First, you need to be logged in...

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Once you set up a shell user and try to log in via SSH, you'll find you must enter your password each time. If you’d like to avoid entering your password every time, you can set up Passwordless Login. This way, you'll be able to automatically login each time immediately without needing to enter your password.

In this article, 'username@server.dreamhost.com' is used as the login example.

The following are instructions on how to set up Passwordless Login for any Unix, Linux, OSX, or Cygwin machine.

STEP ONE – Generating the key pair

On your home computer:

Generate an RSA private key using ssh-keygen (unless you have already created one). If you’re using Linux or Mac OS X, open your terminal and run the following command under your username: [server]$ ssh-keygen -t rsa This creates a public/private keypair of the type (-t) rsa. Generating a public/private rsa key pair. Enter the file in which you wish to save they key (i.e.,...
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Introduction

SSH is in essential tool for any Linux user, but many people aren't making the most of its robust capabilities, namely secure logins with keys.

SSH key pairs allow you to login much more securely by limiting logins to only those computers that possess an encrypted key that has been paired with the login target. Unlike passwords, these keys can't be guessed, so there's no need to worry about someone trying thousands of passwords to break into your computer or server. No key equals no access.

The good news is; these keys are very easy to set up and use, so you don't have to worry about maintaining configurations or wading through a long setup process.

The Need For Keys

If you run a public facing machine, you need these keys. Sorry, but if you're using password authentication, you are more vulnerable.

Passwords are terrible. That's been well known for some time now. Most major web applications and utilities that rely on...

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Tired of typing passwords logging to SSH servers you often access then switching to keys to authenticate will be a game changer. Complex passwords will in general provide a good level of security, but they are tedious and slow to type. Make sure these passwords are strong! Using passwords to authenticate also prevent you from running local scripts that automatic log into other computers (like servers), running tasks or perhaps you want to have a backup/copy running between your laptop and server(s). The good news is that's a simple solution to all of this. I use a machine running OS X in this example, but It is pretty much the same in most Linux and *nix.

SSH and keys, WTF

For you to be able to automatic (unattended) logoin to another machine must this machine have a copy of your machine public key. Your key is signed by what we call a passphrase (you really should use a passphrase). When you then access another machine that that have a copy of your public key, it...

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The ssh program on a host receives its configuration from either the command line or from configuration files ~/.ssh/config and /etc/ssh/ssh_config.

Command-line options take precedence over configuration files. The user-specific configuration file ~/.ssh/config is used next. Finally, the global /etc/ssh/ssh_config file is used. The first obtained value for each configuration parameter will be used.

Commonly used configuration options

There are many configuration options available. In practice, only a few of them are ever changed, and user-specific configuration files are rarely used. In most cases, just /etc/ssh/ssh_config is edited.

Enabling X11 forwarding and agent forwarding

Developers, students, and researchers often want to enable X11 forwarding and SSH agent forwarding. These allow running graphical applications remotely and eliminate the need for typing a password whenever moving from one server to another, respectively. Setting these...

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With RAS key authenticating mechanism, you can login (using SSH ) to a server without providing the password. RSA is an algorithm for public-key cryptography. This process is most suitable for working automated process. For automating backups or run some jobs frequently in a trusted server this will contribute an important role. And the other advantage of RSA key authentication is, it is helpful to connect to the servers which change password frequently. Even if the User Password is changed in the server will not affect the paired computers.

Configure server and client with RSA Key

Create Public and private key using ssh-keygen

#ssh-keygen It will ask for the location to save the key Default location : /root/.ssh/id_rsa Next It will ask passphrase. (u can do it without a password also, for that just enter ) It will create Private key and public key. See the out put Your identification has been saved in /root/.ssh/id_rsa. Your public key has been saved in...
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Trying to connect with

ssh osr@10.17.120.207

should now be passwordless but I'm somehow still getting the prompt for the password...

here's the output from ssh -vvv osr@10.17.120.207

Quote:

interesting are probably the following lines:

Quote:

I have no idea about how to solve this issue...

I hope you know the solution to this problem

Normally, default

Code:

#AuthorizedKeysFile .ssh/authorized_keys

so please check this first.

If yes, then append your public key to a file called authorized_keys

check secure log too.

ssh directory perms 700
authorized_keys file 400 or 600 if being written to
id_dsa 400

Last edited by centosboy; 08-17-2009 at .

secure...

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It is very easy to perform SSH login to the remote server without prompting a password.

With a help of utilities from OpenSSH package, you can generate authentication keys on your local machine, copy public key to the remote server and add identities to your authentication agent.

Just three simple steps separate you from the possibility of connecting to a remote server without prompting a password.

Step 1: Generate a key pair on the local server

Use ssh-keygen to generate authentication keys for SSH.

$ ssh-keygen

Output:

Generating public/private rsa key pair. Enter file in which to save the key (/home/user/.ssh/id_rsa): Created directory '/home/user/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/user/.ssh/id_rsa. Your public key has been saved in /home/user/.ssh/id_rsa.pub. The key fingerprint is: 8c:2a:ed:82:98:6d:12:0a:3a:ba:b2:1c:c0:25:be:5b

Step 2: Install...

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If you don't really want to use a public/private key pair, you can write a expect script to enter the password for you automatically depending on the destination address.

Edit: What I mean is that you can have a script that, on one hand, uses expect to enter the password for you and, on the other hand, reads the password for a given user and host from a configuration file. For example, the following python script will work for the sunny day scenario:

#!/usr/bin/python import argparse from ConfigParser import ConfigParser import pexpect def main(args): url = args.url user, host = url.split('@', 1) cfg_file = 'ssh.cfg' cfg = ConfigParser() cfg.read(cfg_file) passwd = cfg.get(user, host) child = pexpect.spawn('ssh {0}'.format(url)) child.expect('password:') child.sendline(passwd) child.interact() if __name__ == '__main__': parser = argparse.ArgumentParser(description='Run ssh through pexpect')...
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Don't use a password. Generate a passphraseless SSH key and push it to your VM.

If you already have an SSH key, you can skip this step… Just hit Enter for the key and both passphrases:

$ ssh-keygen -t rsa -b 2048 Generating public/private rsa key pair. Enter file in which to save the key (/home/username/.ssh/id_rsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/username/.ssh/id_rsa. Your public key has been saved in /home/username/.ssh/id_rsa.pub.

Copy your keys to the target server:

$ ssh-copy-id id@server id@server's password:

Now try logging into the machine, with ssh 'id@server', and check in:

.ssh/authorized_keys

to make sure we haven’t added extra keys that you weren’t expecting.

Finally check logging in…

$ ssh id@server id@server:~$

You may also want to look into using ssh-agent if you want to try keeping your keys protected with a...

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Used for ssh or scp or anything that needs SSH secure access.

Quick reminder...

If you've done it before but forgot, here's the refresher. (Otherwise, read below.)

On server:

cd .ssh ssh-keygen -t rsa (hit return through prompts) cat id_rsa.pub >> authorized_keys chmod 600 authorized_keys rm id_rsa.pub

On client:

cd .ssh scp myserver.com:.ssh/id_rsa myserver.rsa chmod 600 myserver.rsa echo "Host myserver" >> config echo "Hostname reblets.com" >> config echo "IdentityFile ~/.ssh/myserver.rsa" >> config

Test it:

scp file myserver:. ssh myserver

Background

It's common to use ssh and scp for communicating and transferring files to and from a server. If you want to auto-login without a password, here's how to setup SSH to use encryption keys to do so.

On the Server

Use ssh to login to your server under the account name you want to use.

Run ssh-keygen to create an encryption key pair, the public and private keys....

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Parent page: Internet and Networking >> SSH

Once you have installed an OpenSSH server,

sudo apt-get install openssh-server

you will need to configure it by editing the sshd_config file in the /etc/ssh directory.

First, make a backup of your sshd_config file by copying it to your home directory, or by making a read-only copy in /etc/ssh by doing:

sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config.factory-defaults sudo chmod a-w /etc/ssh/sshd_config.factory-defaults

Creating a read-only backup in /etc/ssh means you'll always be able to find a known-good configuration when you need it.

Once you've backed up your sshd_config file, you can make changes with any text editor, for example;

sudo gedit /etc/ssh/sshd_config

runs the standard text editor in Ubuntu 12.04 or more recent. For older versions replace "sudo" with "gksudo". Once you've made your changes (see the suggestions in the rest of this page), you can apply them by saving the file...

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I wan't to be able to login via ssh with a password and not the key file.
Yeah I know it's totally insecure but at this point in the config I was turning variables off and on left and right trying to get this to work.

# $OpenBSD: sshd_config,v 1.73 2005/12/06 22:38:28 reyk Exp $ # This is the sshd server system-wide configuration file. See # sshd_config(5) for more information. # This sshd was compiled with PATH=/usr/local/bin:/bin:/usr/bin # The strategy used for options in the default sshd_config shipped with # OpenSSH is to specify options with their default value where # possible, but leave them commented. Uncommented options change a # default value. Port 22 #Protocol 2,1 Protocol 2 #AddressFamily any #ListenAddress 0.0.0.0 #ListenAddress :: # HostKey for protocol version 1 #HostKey /etc/ssh/ssh_host_key # HostKeys for protocol version 2 #HostKey /etc/ssh/ssh_host_rsa_key #HostKey /etc/ssh/ssh_host_dsa_key # Lifetime and size of ephemeral version 1 server...
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Introduction

SSH, or secure shell, is an encrypted protocol used to administer and communicate with servers. When working with a Linux server, chances are, you will spend most of your time in a terminal session connected to your server through SSH.

While there are a few different ways of logging into an SSH server, in this guide, we'll focus on setting up SSH keys. SSH keys provide an easy, yet extremely secure way of logging into your server. For this reason, this is the method we recommend for all users.

How Do SSH Keys Work?

An SSH server can authenticate clients using a variety of different methods. The most basic of these is password authentication, which is easy to use, but not the most secure.

Although passwords are sent to the server in a secure manner, they are generally not complex or long enough to be resistant to repeated, persistent attackers. Modern processing power combined with automated scripts make brute forcing a...

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SSH login without password

Your aim

You want to use Linux and OpenSSH to automate 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...
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Introduction

SSH, or secure shell, is a network protocol that provides a secure, encrypted way to communicate with and administer your servers. As SSH is the most common way of working with a FreeBSD server, you will want to familiarize yourself with the different ways that you can authenticate and log in to your server. While there are several ways of logging into a FreeBSD server, this tutorial will focus on setting up and using SSH keys for authentication.

How SSH Keys Work

An SSH server can authenticate clients using a variety of methods. The most common methods include password and SSH key authentication. While passwords do provide a barrier against unauthorized access, using SSH keys is generally much more secure.

The issue with passwords is that they are typically are created manually, without sufficient length or complexity in content. Therefore, they can be susceptible to being compromised by brute force attacks. SSH keys provide a reliably...

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