SSH

SSH (Secure Shell) is both a protocol and the program that implements it. Its primary purpose is remote access to a server over a secure, encrypted channel.

How it works

SSH uses a client-server model. The client authenticates to the server using:

• Password authentication — username and password sent over the encrypted tunnel
• Public-key authentication — the client proves identity using a private key; the server verifies against an authorized public key (more secure, recommended)

Common usage

ssh user@hostname

Connects to hostname as user. If no user is specified, the current local username is used.

Key management

# Generate a new SSH key pair
ssh-keygen -t ed25519
 
# Copy public key to a remote server
ssh-copy-id user@hostname

Related

• gcloud uses SSH to connect to Compute Engine VM instances via gcloud compute ssh <INSTANCE>