SSH

Secure Shell (SSH) is a cryptographic network protocol for secure remote login, command execution, and file transfers.

Installation

• Windows: Install OpenSSH server via PowerShell (Admin): Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
• Linux: sudo apt install openssh-server (Debian/Ubuntu)

Configuration

• Windows (WSL):
  • Administrator accounts: All keys must go to: C:\ProgramData\ssh\administrators_authorized_keys (Windows OpenSSH ignores .ssh\authorized_keys for admin accounts)
  • Non-admin accounts: Use C:\Users\<user>\.ssh\authorized_keys
• Linux: Keys go to ~/.ssh/authorized_keys

Key Management

• Generate keys: ssh-keygen -t ed25519
• Distribute public keys to authorized_keys files on target servers
• Always use key-based authentication instead of passwords

Security

• Disable root login (PermitRootLogin no in sshd_config)
• Use SSH key passphrases
• Restrict access via AllowUsers in sshd_config

Backlink: 2026 04 14 Install SSH and configure to access WSL