SSH or Secure Shell represents a cryptographic network protocol for enabling secure communication of data, command execution, remote shell service or other services via secure network between two computers that are networked and connected through a secure channel but over an insecure network, client and server (running on SSH server/SSH client programs). Typically, SSH is used for logging into remote machines to execute commands.
Why is SSH needed?
SSH helps in establishing a direct and secure connection between two computers within a network that is potentially unsecured. This is essential to prevent third parties from accessing the data stream and the data, consequently, falling into the wrong hands. Before the advent of SSH, means of establishing a direct connection between computers was available through applications like Remote Shell, Telnet, Riogin etc. However, these were unsecured mediums of connecting two systems. With SSH, the connection between computers is encrypted.
Apart from providing encrypted connection, SSH also makes sure that only designated computers are connected so that you can be free from the fear of attacks from the ‘man in the middle’. SSH enables you to log into your VPS Server Hosting remotely. Once connected, SSH will also enable you to issue commands just as if you were sitting right at the server. Besides, there are several applications of SSH, and some of them include:
- Transmitting files securely
- Managing VPS Server Hosting remotely
- Creating secure backups
- Connecting two computers with encryption end-to-end
- Maintaining other computers remotely.
With the introduction of SSH, other products have also entered the market, including unsecured FTP protocol useful in downloading files from servers and uploading them. This has also been further upgraded as SFTP. A specific advantage of SSH is that its protocol can run on nearly every common operating system. Although SSH originally started as a Unix application, it can presently be used on Linux distribution/macOS too. You can use SSH on windows after installing additional programs such as puTTY.
SSH Compared To Open SSH
Originally SSH was created in 1995 and was an open-source project. However, the protocol was further developed as proprietary software. The network community failed to accept this and, in the result, SSH-1 evolved. As a consequence, there are two protocols running concurrently and competing with each other. In later days, SSH-1 experienced security vulnerabilities giving birth to SSH-2 protocol. The commercial SSH and Open SSH remain nearly similar with regard to scope and functionality.
The major difference between these two lies in support and cost. 24/7 support is available for SSH communication security package. For large establishments with different IT managers in-charge, this could be useful. On the other hand, open SSH comes with the advantages tied to the open-source community, which in turn means that the product is undergoing constant development by multiple participants.
Using SSH In Virtual Server Web Hosting
SSH employs multiple authentications and encryption techniques. This helps in ensuring that data streams cannot be manipulated or read. Similarly, contact is possible only between authorized participants.
The first step in the authentication process is the client and the SSH server authenticating each other. The server sends a certificate, and the client verifies that it is on the right server. When contact is established, there is a possibility of someone intercepting the connection. However, with the certificate also encrypted, there is no way someone can imitate it. Since the client can identify the correct certificate, no intruder can get into the data stream or disrupt the activity.
After the server is authenticated, the client should also identify as an authorized entity for access to the server. A password may be employed to achieve this. Every time a user logs on to different servers across the same session, he may need to repeat the password. However, an alternative to this is the use of a private and public key pair. For the private key, user can use his computer and secure it with a passphrase which is longer compared to typical passwords. The private key is permanently stored in the same computer in which it is created and thus remains secrete.
When an SSH connection needs to be established, the user enters the passphrase for the private key, and that provides access to the private key. The server will also have public keys, and the server generates a cryptographic problem using its public key and relays it to the client. Subsequently, the server decrypts the problem using its private key and relays the solution back informing the server that legitimate connection can now be established. Users should take care to log off at the end of every session so that third parties who have physical access to the computer are prevented from accessing the server.
Virtual private server hosting comes with root SSH access. This allows you to change anything on the server as per your requirement. Generally, port 22 or port 2222 is used to connect to the server with the username as “root.” You can enable the SSH access from your cPanel, and if an “error” message appears, you may have to be verified. It is required that you add your IP address to the firewall to successfully using SSH to log in to your Virtual Server Hosting.