SSH stands for Secure Shell and it is a commonly used protocol for controlling the remote servers over the Internet. The service is established for our Hosting servers with Linux OS on it (provided from our side) by default.
So, in case you are experiencing issues with connecting your server on Linux from us using SSH, this article will help you to address it and will provide you with basic troubleshooting steps and some possible root-causes behind the issue.
1. Let's start from basic troubleshooting of SSH connection issues.
First of all, we need to remember that the default port used by SSH is 22 port. Thus, our first step is to test the connectivity over this port. To do that we can use telnet command on any other Linux machine or just trying to connect via SSH (using PuTTY utility, for example).
Here are the samples of running telnet:
telnet 92.000.000.00 22
Where 92.000.000.00 – is the server's IP аnd 22 – is its port.
If you see this kind of result, it means the server can be connected via SSH.
telnet 92.000.000.00 22
Trying 92.000.000.00...
Connected to 92.000.000.00
Escape character is '^]'.
SSH-2.0-OpenSSH_9.0p1 Ubuntu-1ubuntu8
Connection closed by foreign host.
Here is how Putty interface looks like:
In order to try the SSH connection out, you need to specify the IP address in the respective field and to make sure you still have 22 port within the Port field. Once it is done you are good to hit the Open button.
The following screen will pop up (if you are connecting the server for the first time or clicked Connect once before):
You will need to follow the instructions and choose if you want to Accept and add the key to PuTTY's cache permanently or Connect Once if you want to continue without it.
Then you will be prompted to enter your server credentials (you can find it in the Instruction or the e-mail ta was sent to you upon the server's activation). In the terminal the word 'login' will be used instead of the 'User':
If you are able to get to this step and are asked to enter the credentials, it means that 22 port is opened and you are able to connect the server.
2. If you are still having issues with establishing the connection, the issue might be with the credentials and you need to double-check your server's login and password.
You need to find both your login and your password in the Control Panel for that. Choose the server and then click the Instructions button.
You should look for the User and the Password fields located after the Server IP address.
Note: If you change the password in the OS by yourself it won't change in the Instruction.
3. In case of still having errors when testing the connectivity via telnet, Putty or any other convenient tool for connecting the server via SSH, first of all, it is better to ensure that your server is working/available via Internet at all (this guide may come in handy).
4. If the server itself is okay, please, check the settings for SSH service within the OS. This can be easily achieved by connecting the server via VNC in VMmanager (for a Virtual Private Server) or IPMI in DCImanager (for a Dedicated Server). The credentials to access the respective panels can be found in the Instruction as well.
5. There also could be an additional case when you are connecting as usual, but suddenly you start receiving the following error:
----------@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:mN0OlpZpdkJJIRjFvNJ1aCS0oMzkW+mY4jyFLk7qXzM.
Please contact your system administrator.
Add correct host key in /Users/User/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /Users/User/.ssh/known_hosts:1
Host key for IP has changed and you have requested strict checking.
Host key verification failed.
Usually such an error occurs when you are connecting from Windows using the command line (it is not an issue when you are connecting via Putty, for example) and only after reinstalling the OS on the server. The issue is caused by the fact that when connecting to the server via SSH using the cmd for the first time, your SSH client saves the host (to be more precise, the ECDSA host key) to its C:\Users\%username%\.ssh\known_hosts file and after reinstalling the OS on the server the host changes. The console detects that the server is the same, but the host has changed and prompts this security error.
In this case you can add a new host's data to C:\Users\%username%\.ssh\known_hosts or just delete this file.
If you're sure that the port 22 is not blocked from your side, nothing above helps or, for instance, you simply changed the password previously and forgot it, feel free to contact our Technical Support team and we will help you!
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