VMmanager Documentation (user)

SSH protocol

ISPSystem

SSH is a network protocol used to establish remote access to servers via an encrypted channel. It utilizes a user of a remote server to get connected and the password or SSH keys for authorization.

SSH in VMmanager


VMmanager uses SSH to provide access to virtual machines. SSH keys are used for authorization.

The platform stores all open user keys and saves them automatically on virtual machines to the file /root/.ssh/authorized_keys. This feature is only available in Linux if an OS template supports it.

Open SSH keys can be specified in Client area → SSH keys. Read more in Profile settings.

SSH server


An SSH server is a set of resources used to manage servers remotely and transfer files by using the SSH protocol.

VMmanager uses the OpenSSH server.

The OpenSSH client must have the openssh-client package installed, while the server must have the openssh-server package. The server component of OpenSSH will constantly wait for client connections from any client application.

SSH connection with login and password


Connect your OpenSSH client to the server with the following command:

ssh user@host

user is a remote server user account.

host is an IP address of the remote server.

Enter the remote user password to get connected.

SSH connection with SSH keys


SSH keys

SSH keys are a couple of keys actually: one open and one closed. The closed key is the secret information stored by the user. The open key must be stored on the server which you connect via SSH to.

Generate a key 

In Linux systems, keys are generated in the following way:

ssh-keygen [options]

Main parameters: -t for encryption algorithm and -b for key length:

ssh-keygen -t rsa -b 4096
ssh-keygen -t dsa
ssh-keygen -t ecdsa -b 521
ssh-keygen -t ed25519

The system will request to specify a directory and names for the files that will have the keys. The open key will also have the ending ".pub".

Copy an open key

An open user key needs to be copied to the server which you need SSH access to. The key is to be copied to ~/.ssh/authorized_keys:

ssh-copy-id -i ~/.ssh/id_rsa.pub user@host

user is a remote server user account.

host is an IP address of the remote server.

~ is a directory of a home folder of the remote server user.

You will need to enter the remote user password to get connected.

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