What Is SSH?
SSH — Secure Shell — is a cryptographic network protocol that lets you securely connect to remote machines, transfer files, tunnel traffic, and automate infrastructure operations over any network, including the open internet. It was created in 1995 by Tatu Ylönen as a direct response to a password-sniffing attack at his university. In the thirty years since, it has become the foundational protocol of the entire modern internet's operational layer.
If you have ever run git push to GitHub, deployed code to a cloud server, used a CI/CD pipeline, managed a Linux machine, or connected to a remote database, you have interacted with SSH — whether you knew it or not.
What Problem Does SSH Solve?
Before SSH, the standard tools for remote server access were telnet, rsh, and rlogin. These protocols transmitted everything in plaintext: your username, your password, every command you typed, every file you transferred. Anyone on the same network segment with a packet sniffer could read all of it.
