SSH Cheatsheet
Overview
- SSH (Secure Shell) is a protocol used for secure remote access to a machine over an unsecured network.
- It provides encrypted communication between the client and the server, preventing eavesdropping, tampering, and other security threats.
- SSH is commonly used for remote shell access, file transfers, and tunneling.
Basic Usage
- Connect to a remote machine:
ssh username@remote_host
- Connect to a remote machine on a specific port:
ssh -p port_number username@remote_host
- Copy a file from a remote machine to the local machine:
scp username@remote_host:/path/to/remote/file /path/to/local/directory
- Copy a file from the local machine to a remote machine:
scp /path/to/local/file username@remote_host:/path/to/remote/directory
Key Management
- Generate an SSH key pair:
ssh-keygen
- Copy the public key to a remote machine:
ssh-copy-id username@remote_host
- Add a private key to the SSH agent:
ssh-add /path/to/private/key
- List the keys in the SSH agent:
ssh-add -l
Security
- Disable root login: Edit
/etc/ssh/sshd_config and set PermitRootLogin no
- Use key-based authentication: Edit
/etc/ssh/sshd_config and set PasswordAuthentication no
- Use a strong passphrase for the private key:
ssh-keygen -p
Resources