SSH on Linux: How to Connect to a Server — Definitive Guide

What Is SSH?

Secure Shell (SSH) is the standard protocol for interacting securely with remote Linux servers. It encrypts all traffic, so your passwords and data stay safe.

Basic command

With username and password:

ssh username@ip-address

Beyond Passwords: SSH Keys

Passwords are vulnerable to brute force. The "pro" way is SSH key pairs.

1. Generate your key

On your local machine:

ssh-keygen -t ed25519 -C "your_email@example.com"

This creates a private key (~/.ssh/id_ed25519) and a public key (~/.ssh/id_ed25519.pub).

2. Copy the key to the server

ssh-copy-id username@ip-address

After that you can log in without a password. Faster and much more secure.

Harden the Server

Once in, tune /etc/ssh/sshd_config:

• Disable root login: PermitRootLogin no
• Disable password auth: PasswordAuthentication no
• Change default port: e.g. from 22 to 2222 to avoid most bot scans

Restart the service:

sudo systemctl restart ssh

Pro Tips

• SSH config: Save connections in ~/.ssh/config so you can type ssh myserver
• Mosh: Use it on mobile or unstable networks
• Tmux: Start a Tmux session so your work survives disconnects