This page is about the SSH protocol. For the company behind it, see SSH Communications Security. For using the Linux ssh command, see ssh command usage. For SSH clients, servers, and technical information, see SSH (Secure Shell) home page. The SSH protocol (also referred to as Secure Shell) is a method for secure remote login from one computer to another. It provides several alternative options for strong authentication, and it protects communications security and integrity with strong encryption. It is a secure alternative to the non-protected login protocols (such as telnet, rlogin) and insecure file transfer methods (such as FTP). Typical uses of the SSH protocol How does the SSH protocol work Strong authentication with SSH keys SSH provides strong encryption and integrity protection IETF SSH standard and detailed technical documentation The core protocol SFTP file transfer protocol Public key file format How to Cite SSH The protocol is used in corporate networks for: providing secure access for users and automated processes interactive and automated file transfers issuing remote commands managing network infrastructure and other mission-critical system components. The protocol works in the client-server model, which means that the connection is established by the SSH client connecting to the SSH server. The SSH client drives the connection setup process and uses public key cryptography to verify the identity of the SSH server. After the setup phase the SSH protocol uses strong symmetric encryption and hashing algorithms to ensure the privacy and integrity of the data that is exchanged between the client and server. The figure below presents a simplified setup flow of a secure shell connection. There are several options that can be used for user authentication. The most common ones are passwords and public key authentication. The public key authentication method is primarily used for automation and sometimes by system administrators for single sign-on. It has turned out to be much more widely used than we ever anticipated. The idea is to have a cryptographic key pair - public key and private key - and configure the public key on a server to authorize access and grant anyone who has a copy of the private key access to the server. The keys used for authentication are called SSH keys. Public key authentication is also used with smartcards, such as the CAC and PIV cards used by US government. The main use of key-based authentication is to enable secure automation. Automated secure shell file transfers are used to seamlessly integrate applications and also for automated systems & configuration management. We have found that large organizations have way more SSH keys than they imagine, and managing SSH keys has become very important. SSH keys grant access as user names and passwords do. They require a similar provisioning and termination processes. In some cases we have found several million SSH keys authorizing access into production servers in customer environments, with 90% of the keys actually being unused and representing access that was provisioned but never terminated. Ensuring proper policies, processes, and audits also for SSH usage is critical for proper identity and access management. Traditional identity management projects have overlooked as much as 90% of all credentials by ignoring SSH keys. We provide services and tools for implementing SSH key management. Once a connection has been established between the SSH client and server, the data that is transmitted is encrypted according to the parameters negotiated in the setup. During the negotiation the client and server agree on the symmetric encryption algorithm to be used and generate the encryption key that will be used. The traffic between the communicating parties is protected with industry standard strong encryption algorithms (such as AES (Advanced Encryption Standard)), and the SSH protocol also includes a mechanism that ensures the integrity of the transmitted data by using standard hash algorithms (such as SHA-2 (Standard Hashing Algorithm)). When the SSH protocol became popular, Tatu Ylonen took it to the IETF for standardization. It is now an internet standard that is described in the following documents: RFC 4251 - The Secure Shell (SSH) Protocol Architecture RFC 4253 - The Secure Shell (SSH) Transport Layer Protocol RFC 4252 - The Secure Shell (SSH) Authentication Protocol RFC 4254 - The Secure Shell (SSH) Connection Protocol The SFTP (SSH File Transfer Protocol) is probably the most widely used secure file transfer protocol today. It runs over SSH, and is currently documented in draft-ietf-secsh-filexfer-02 The public key file format is not a formal standard (it is an informational document), but many implementations support this format. RFC 4716 - The Secure Shell (SSH) Public Key File Format To cite SSH in a research paper, please use the following:Contents
Typical uses of the SSH protocol
How does the SSH protocol work
Strong authentication with SSH keys
SSH provides strong encryption and integrity protection
IETF SSH standard and detailed technical documentation
The core protocol
SFTP file transfer protocol
Public key file format
How to Cite SSH
Tatu Ylonen: SSH - Secure Login Connections over the Internet.
Proceedings of the 6th USENIX Security Symposium, pp. 37-42, USENIX, 1996.
FAQs
What is the Secure Shell (SSH) Protocol? | SSH Academy? ›
The SSH protocol uses encryption to secure the connection between a client and a server. All user authentication, commands, output, and file transfers are encrypted to protect against attacks in the network.
What is SSH Secure Shell protocol? ›SSH (Secure Shell or Secure Socket Shell) is a network protocol that gives users -- particularly systems administrators -- a secure way to access a computer over an unsecured network.
What is the Secure Shell SSH protocol quizlet? ›Secure Shell (SSH) is a remote administration protocol that allows users to control and modify their remote servers over the internet.
Which port ____ is used for Secure Shell SSH? ›Secure Shell (SSH) uses a default TCP port of 22.
What is Secure Shell reddit? ›SSH stands for Secure SHell it is a protocol to connect to a remote system. The default port is 22 however some people who practice security through obfuscation will use completely different port numbers this is not a recommended practice.
What is the SSH used for? ›SSH or Secure Shell is a network communication protocol that enables two computers to communicate (c.f http or hypertext transfer protocol, which is the protocol used to transfer hypertext such as web pages) and share data.
What does the SSH command do? ›The ssh command provides a secure encrypted connection between two hosts over an insecure network. This connection can also be used for terminal access, file transfers, and for tunneling other applications. Graphical X11 applications can also be run securely over SSH from a remote location.
Which of the following does SSH Secure Shell provide? ›SSH provides strong encryption and integrity protection
During the negotiation the client and server agree on the symmetric encryption algorithm to be used and generate the encryption key that will be used.
SSH port 22
By default, port 22 is open on all IBM StoredIQ hosts. The port is used for Secure Shell (SSH) communication and allows remote administration access to the VM. In general, traffic is encrypted using password authentication.
SSH provides more security for remote connections than Telnet does by providing strong encryption when a device is authenticated. This software release supports SSH Version 1 (SSHv1) and SSH Version 2 (SSHv2). SSH functions the same in IPv6 as in IPv4.
How to secure a SSH connection? ›
- Require strong passwords. Require passwords that are at least twelve characters long, and combine uppercase and lowercase letters, numbers, and special characters.
- Enable two-factor authentication. ...
- Regularly update passwords. ...
- Implement account lockouts. ...
- Educate users. ...
- Use SSH keys.
SSH, or Secure Shell, is an essential protocol for securely accessing and managing remote servers. It encrypts all communication, ensuring that data remains protected from unauthorized interception. By default, SSH runs on port 22, which is often targeted by brute force attacks.
What is the SSH Secure Shell? ›What is the Secure Shell (SSH) protocol? The Secure Shell (SSH) protocol is a method for securely sending commands to a computer over an unsecured network. SSH uses cryptography to authenticate and encrypt connections between devices.
What is the Secure Shell SSH Transport Layer protocol? ›The Secure Shell (SSH) is a protocol for secure remote login and other secure network services over an insecure network. This document describes the SSH transport layer protocol, which typically runs on top of TCP/IP. The protocol can be used as a basis for a number of secure network services.
How do I OpenSSH Secure Shell? ›- Open the terminal (command line interface) on your computer. ...
- You will see the name of your user on your terminal screen and a blinking cursor. ...
- The command to log in via SSH is ssh. ...
- Press Enter.
- A prompt will appear asking for your server's root password.
- Open the terminal on your computer.
- Type ssh, followed by a space. ...
- If you see a message stating “Are you sure you want to continue connecting” type yes, then click the Enter key.
- You will then be prompted to enter your password.
However, the key difference between SSH and SSL is that SSH is used to create a secure tunnel to another computer from which you can transfer data, issue commands, etc. Whereas SSL is used to transfer data between two parties securely. You won't be able to issue commands like with SSH.
How to use SSH Secure Shell client? ›- Start PuTTY.
- In the Host Name (or IP address) text box, type the hostname or IP address of the server where your account is located.
- In the Port text box, type 7822. ...
- Confirm that the Connection type radio button is set to SSH.
- Click Open.
Does SSH use TLS or SSL? SSH doesn't use Transport Layer Security (TLS) protocols or Secure Socket Layer (SSL). To be clear, TLS is the successor to SSL, so they're considered synonyms. TLS/SSL is used for encryption in the HTTPS and FTPS protocols, not the SFTP protocol.