SSH Port Guide: What Port Does SSH Use?

Need to handle server connections from afar safely? SSH (Secure Shell) is your best choice. It protects your info by encrypting chats between your computer and a server. Knowing which SSH port to use is key to using it well.

Since July 1995, SSH normally uses port 22. But, you can up your safety by using a different port instead. This guide will show you not only why port 22 is usually picked but also how to make your setup safer.

Introduction to SSH and Its Default Port

Secure Shell, also known as SSH, is a secure way to communicate over a network. It was made to be much safer than telnet, which had no encryption. This means with SSH, everything you send or receive is encrypted, keeping your data safe.

The default port for SSH is port 22. This port plays a big role in making sure connections are secure. Through port 22, SSH creates a safe path over an unsafe network. This lets users safely execute commands, set up services, and transfer files.

SSH uses public and private keys to check who you are. You get a public key for encryption and a private key for decryption. This system is much more secure than just using passwords. It uses complex cryptography like RSA and the Digital Signature Algorithm.

For encryption, SSH also uses methods like DES and AES. It turns data into a fixed-length hash value through hashing functions. This adds another layer of security to your data.

SSH can also create secure tunnels. This feature allows you to safely connect networks over encrypted channels. It ensures that any data transferred or commands executed are kept secret from outsiders.

Using the default SSH port makes setting up secure connections easy. Knowing and using SSH can greatly boost the security of your network tasks. It helps protect your information and gives you peace of mind.

Why Port 22: The Story Behind the Default SSH Port

Port 22 is known for being the default for Secure Shell (SSH) protocols. This story starts back in 1995 with Tatu Ylonen. He invented SSH to replace older, less secure systems like telnet and FTP. Thanks to SSH, it became easy to move data securely and work on remote terminals. This advancement helped protect data from being stolen and solved many security issues.

The Origin

Tatu Ylonen is the brains behind SSH. He developed it in the mid-1990s to make data communication over networks safer. At a time when internet security needed a boost, SSH was a major leap. It introduced three key protocols to greatly improve data security.

Why Port 22 Was Chosen

Choosing port 22 for SSH was not random. It sits right between the ports for telnet (port 23) and FTP (port 21). This made it easier for users familiar with these old protocols to switch to SSH. Placing it between these ports ensured a smoother change for system administrators to a more secure system.

The Process of Port Allocation

The Internet Assigned Numbers Authority (IANA) officially gave SSH port 22. Jon Postel and Joyce K. Reynolds played big roles in this decision. They wanted to make the internet safer and more efficient. Port 22 was chosen for SSH to promote safer networking and reduce security threats.

When assigning internet ports, there’s a focus on smart placement, ease for users, and tight security. These factors explain why port 22 is specifically used for SSH. It shows the careful thinking behind using port 22 for Secure Shell.

What Port Does SSH Use?

Secure Shell (SSH) is key for secure server management. By default, SSH servers use port 22, known as the TCP port for SSH. This standard SSH port allows for SSH connections using encryption like AES and Blowfish. It keeps communication between systems safe.

SSH-1, the first version, was replaced due to security issues. In 2006, the Internet Engineering Task Force (IETF) introduced SSH-2. It came with better security, like Diffie-Hellman key exchange and strong integrity checks. These changes made SSH connections much safer.

Handling host keys on client systems with care is crucial. If not, it leads to unauthorized access, harming secure server management. So, making, changing, and removing SSH keys are important for security.

Even though SSH-2 is secure, it’s not risk-free. Edward Snowden’s leaks hinted at NSA’s ability to decrypt some SSH traffic. Also, the Shellshock vulnerability has indirectly affected SSH, introducing further risks.

Knowing about the standard SSH port helps you get better at secure server management. It helps you set up and protect your SSH servers properly.

Changing the Default SSH Port

Enhancing server security can start with changing the default SSH port, usually set to 22. This change makes the server less of a target for brute-force attacks. By choosing a non-standard port, you can greatly improve your server’s safety.

Reasons to Change the Default Port

SSH servers by default listen on port 22. This makes them a big target for automated attacks. Switching to a less obvious port helps avoid these attacks. It also reduces network issues and lowers the chance of unauthorized access, leading to better security.

Step-by-Step Guide

Here’s a simple guide to change the SSH port:

1. Edit the sshd_config file: Use a text editor to open the SSH configuration file:

   sudo nano /etc/ssh/sshd_config

2. Modify the Port directive: Find Port 22 and change it to a new port, like 2222 or another above 1024:

   # Port 22
   Port 2222

3. Update firewall rules: Adjust your firewall to allow access to the new port. Here’s how with iptables:

   sudo iptables -A INPUT -p tcp --dport 2222 -j ACCEPT

   Or for UFW users:

   sudo ufw allow 2222/tcp

4. Restart the SSH service: Restart SSH to apply the new settings:

   sudo systemctl restart sshd

Testing the Changes

After updating the SSH port, it’s important to make sure everything works:

1. Open a new terminal window: Connect to your server with the new port, like this:

   ssh username@your_server_ip -p 2222

2. Validate the connection: This step checks if your connection is successful, preventing server lockout.
3. Close the default port: If everything checks out, close port 22 to boost security:

   sudo ufw delete allow 22/tcp

By carefully setting up your SSH port, updating firewall rules, and checking the changes, you create a strong defense against threats. This ensures your server stays secure.

Configuring SSH Access Through Firewalls

Allowing SSH access through firewalls is key to strong network security. Firewalls act as a barrier, filtering traffic using set rules. For SSH, knowing firewall rules for SSH greatly aids in securing remote connections.

SSH uses port 22 for safe remote logins and file transfers. Typically, firewall rules for SSH should allow traffic on this port. Yet, for extra security, changing the default port to a less common one, like port 2222, is wise.

• iptables configuration: Command sets for firewall setups are crucial. Here are the commands to enable SSH traffic:
• iptables -A INPUT -p tcp --dport 22 -j ACCEPT for the standard port
• iptables -A INPUT -p tcp --dport 2222 -j ACCEPT for an alternative port

Administrators often turn to OpenSSH for more detailed control. For example, AllowTcpForwarding lets you do TCP forwarding, important for SSH tunnels. Also, GatewayPorts configuration decides if forwarded ports can be reached from afar.

Here’s some best practices:

1. Avoid port forwarding when it’s unnecessary to lower security risks.
2. Consider secure solutions like Tectia SSH for better features and strong support for SFTP.

With clear firewall rules and iptables configuration, enhancing network security while supporting safe SSH use is achievable.

Conclusion

Understanding Secure Shell (SSH) is key to strong security in system management. SSH normally uses port 22. Yet, with 65,536 ports available, changing the default can boost security. Proper SSH setup, like editing the sshd_config file or using port forwarding, helps protect against cyber threats. This ensures safe, continuous remote server access.

Following top SSH setup tips can greatly improve your security. This includes using public key pairs for logging in and setting up SSH keys for automated tasks and backups. By using SSH Port Forwarding, including Local, Remote, or Dynamic Forwarding, you increase your network’s security. Adding tools like SSH Agent or Proxy Servers can protect against unwanted access and data leaks.

To really secure SSH communications, take extra steps upfront. Ensure you configure a strong SSH timeout and choose a secure port number. Also, use Public Key Authentication to make your network stronger. As SSH evolves to handle more online and network traffic, staying updated on these methods is vital. It helps network administrators protect their systems well.