Glossary

SSH

SSH (Secure Shell) is a protocol for securely connecting to a remote server over a network. It replaced the insecure Telnet, which sent data in plain text. Every developer who deploys to a VPS or uses a Git repository uses SSH daily.

Authentication

Password-based — convenient but vulnerable to brute force. Better to disable it
Key-based — a private/public key pair. The private key stays with you; the public key goes on the server in ~/.ssh/authorized_keys. Secure and convenient

Common commands

ssh user@server.com           # connect
ssh-keygen -t ed25519         # generate keys
ssh-copy-id user@server.com   # copy public key

SSH Tunneling

SSH lets you forward a local port through an encrypted tunnel — for example, connecting to a production database from your laptop without exposing the DB port to the internet.