SSH (Secure Shell) is a secure protocol for accessing remote servers. It allows administrators to control and manage servers remotely. In this guide, we’ll explore how to connect to SSH from a Linux or Ubuntu desktop in three scenarios:
- Without specifying an SSH port (default port 22).
- With a custom SSH port.
- Using a custom port along with
.ppkor.pemfiles. - Steps to Save SSH Connections in the SSH Config File
1. Connect to SSH Without Specifying a Port
The default SSH port is 22, so if the server uses the default port, no additional configuration is needed.
Steps to Connect
- Open the Terminal on your Linux/Ubuntu desktop.
- Use the following command:Replace
usernamewith the SSH username andserver_ipwith the IP address of the remote server.
Example:
What Happens:
- The SSH client connects to port
22by default. - You’ll be prompted to enter the password for the user.
2. Connect to SSH with a Custom Port
If the server is configured to use a non-default SSH port, you need to specify it in the command.
Steps to Connect
- Determine the custom port number configured on the server (e.g.,
2222). - Use the
-poption in the SSH command to specify the port:
Example:
What Happens:
- The SSH client connects to the specified custom port.
- Enter the password when prompted.
3. Connect to SSH with a Custom Port Using .ppk or .pem Files
Private keys (.ppk or .pem) are often used for passwordless SSH authentication.
For .pem File:
Ensure the
.pemfile is on your local system and has the correct permissions:chmod 600 keyfile.pem
Use the
-ioption with the SSH command to specify the private key:ssh -i /path/to/keyfile.pem username@server_ip -p port_number
Example:
For .ppk File:
Linux SSH clients typically use .pem files. To use a .ppk file, convert it to .pem format using
puttygen:
- Install
putty-toolsif not already installed: - Convert the
.ppkfile to.pem: - Use the converted
.pemfile as shown in the previous example.
4. Steps to Save SSH Connections in the SSH Config File
Locate or Create the SSH Config File
- Open a terminal and navigate to the
.sshdirectory in your home folder: - If the
configfile doesn’t exist, create it:
- Open a terminal and navigate to the
Edit the Config File
- Open the
configfile in a text editor, such asnanoorvim:
- Open the
Add SSH Connection Details Add the details of your SSH connection to the file. Below are examples for each scenario:
Example 1: Default SSH Port
Example 2: Custom SSH Port
Example 3: Custom Port with
.pemor.ppkFileSave and Exit
- For
nano, pressCtrl + O, thenEnterto save, andCtrl + Xto exit.
- For
Connect Using the Shortcut
- Use the
Hostname defined in the config file as a shortcut:oror
- Use the
Benefits of Using the SSH Config File
- Shortcuts: No need to remember IP addresses, usernames, ports, or key file paths.
- Automation: Simplifies scripts or cron jobs that require SSH connections.
- Organization: Manage multiple server connections easily in one file.
Advanced Tip: Test Your Connection
To verify that your configuration works, use the -v flag (verbose mode):
Now, you can connect to your servers effortlessly with saved configurations!
