This article provides steps for connecting to a cloud server froma computer running Linux® or MacOS® X by using Secure Shell (SSH).It also discusses generating an SSH key and adding a public key tothe server.
May 04, 2015 Verified and Tested 2/8/15 Introduction. This guide will show you how to generate and use SSH keys (public and private) using PuTTYgen and PuTTY for Linux servers. How to Generate and Use an SSH Key. Sep 26, 2019 Manually generating your SSH key in Windows ›. You can use PuTTY to generate SSH keys. PuTTY is a free open-source terminal emulator that functions much like the Terminal application in macOS in a Windows environment. This section shows you how to manually generate and upload an SSH key when working with PuTTY in the Windows environment.
SSH is a protocol through which you can access your cloud server and runshell commands. You can use SSH keys to identify trusted computers withoutthe need for passwords and to interact with your servers.
SSH is encrypted with Secure Sockets Layer (SSL), which makes it difficultfor these communications to be intercepted and read.
Note: Many of the commands in this article must be run on your localcomputer. The default commands listed are for the Linux command line orMacOS X Terminal. To make SSH connections from Windows®, you can use a clientsimilar to the free program, PuTTY.To generate keys, you can use a related program, PuTTYGen.
Using the Internet Protocol (IP) address and password for your cloud server, log in byrunning the following ssh command with username@ipaddress as the argument:
The system prompts you to enter the password for the account to which you’reconnecting.
If you rebuilt your cloud server, you might get the following message:
One of the security features of SSH is that when you log in to a cloudserver, the remote host has its own key that identifies it. When you tryto connect, your SSH client checks the server’s key against any keysthat it has saved from previous connections to that IP address. After yourebuild a cloud server, that remote host key changes, so your computerwarns you of possibly suspicious activity.
To ensure the security of your server, you canuse the web console in the Cloud Control Panel to verify your server’s new key.If you’re confident that you aren’t being spoofed, you can skip thatstep and delete the record of the old SSH host key as follows:
On your local computer, edit the SSH known_hosts file and remove anylines that start with your cloud server’s IP address.
Note: Use the editor of your choice, such as nano on Debian or theUbuntu operating systemor vi on RPM or CENTOS servers. For simplicity, this article just uses nano. If you prefer to use vi,substitute vi for nano in the edit commands.For more on using nano, seehttps://support.rackspace.com/how-to/modify-your-hosts-file/.
If you are not using Linux or MacOS X on your local computer, thelocation of the known_hosts file might differ. Refer to your OS forinformation about the file location. Step by step instructions generate ssh key github. PuTTY on Windows gives you theoption to replace the saved host key.
You can secure SSH access to your cloud server against brute forcepassword attacks by using a public-private key pair. A public key is placed onthe server and a matching private key is placed on your local computer. If youconfigure SSH on your server to accept only connections using keys,then no one can log in by using just a password. Connecting clientsare required to use a private key that has a public key registered onthe server. For more on security, reviewLinux server security best practices.
Use the following steps to generate an SSH key pair:
Run the following command using your email address as a label.Substitute your email address for your_email@example.com inthe command.
A message indicates that your public-private RSA key pair isbeing generated.
At the prompt, press Enter to use the default location or entera file in which to save the key and press Enter.
If you want the additional security of a password for the key pair,enter a passphraseand press Enter. If you don’t want to use a passwordwith the key pair, press Enter to continue without setting one.
Your key pair is generated, and the output looks similar to the following example:
Optionally, add your new key to the local ssh-agent file to enableSSH to find your key without the need to specify its location everytime that you connect:
You can use an SSH configuration shortcut instead of the ssh-agent fileby following the instructions in the Shortcut configuration sectionlater in this article.
To make it easy to add your key to new cloud servers that you create,upload the public key to your cloud account by following these steps:
Paste the contents of the id_rsa.pub file that you created intothe Public Key field. You can get the file contents by eitheropening the file in a text editor or by running the followingcommand:
If you want to add the key manually, instead of by using the Control Panel, reviewLinux server security best practicesand use the following command:
When you create a new cloud server, you can add a stored key to the newserver.
On the Create Server page, expand the Advanced Options section.
From the SSH Key menu, select your key from the list.
If you don’t see a stored key in the list, you can perform one of the following actions:
You can’t use the Cloud Control Panel to add a public key to anexisting server. greek font for mac download Follow these steps to add the key manually:
On your cloud server, create a directory named .ssh in the homefolder of the user that you connect to by using SSH.
Create or edit the authorized_keys file and add your public key tothe list of authorized keys by using the following command:
A key is all on one line, so ensure that the key isn’t broken byline breaks. You can have multiple keys in the authorized_keysfile, with one key per line.
Set the correct permissions on the key by using the following commands:
If you have any issues and need to fix permissions issues, run the following comand:
After you have added the public key to the authorized_keys, you can make an SSHconnection by using your key pair instead of the account password.
Use the following instructions to set up a connection shortcut by creating a~/.ssh/config file on your local computer and adding your server and keydetails to it.
Using a text editor, add the following text to the ~/.ssh/config file, changing thevalues to match your server information:
Each of the following entries describes a feature of the server:
After you set up the config file, connect to the server by usingthe following command with your shortcut name:
If you have trouble making a new connection after you restart theserver, use the following steps to help you resolve the issue:
The best way to troubleshoot SSH or SFTP login issues is to attempt tologin through SSH while logged into the Emergency Console and to watch the log,which typically includes the reason for a failure. If no reason is given,it could be a firewall issue. For RPM servers, run the following command to watch the log:
For Debian servers, run the following command to watch the log:
connection timeout error, check the IP address thatyou used to ensure that it’s correct. You might also check theserver’s iptables to ensure that it isn’t blocking the port used by SSH.connection refused error, you might be trying to useSSH with the wrong port. If you changed your server to listen to aport other than 22, use the -p option with SSH to specifythe port.sshd configuration to allow passwordconnections by setting PasswordAuthentication to yes. Restartthe server and try again. If you connect after these changes, thenthe issue is with the key and you must verify that the key is in theright place on the server.If all else fails, review your changes and restart the SSH daemon onthe server by running the following command:
If you get a message that the SSH service is unknown, run thecommand with sshd as the service name instead.
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