linux-ssh-init-sh/README.md

Linux Server Init & SSH Hardening Script (linux-ssh-init-sh)

📖 English | 📖 中文文档

---

📖 English

A production-ready, POSIX-compliant shell script designed to initialize Linux servers and harden SSH security in minutes.

✨ Key Features

• Universal Compatibility: Works flawlessly on Debian 10/11/12, Ubuntu, CentOS 7/8/9, Alma/Rocky, and Alpine Linux.
• POSIX Compliant: Written in pure /bin/sh. No bash dependency.
• Safety Architecture:
  • Managed Config Block: Inserts configuration at the top of sshd_config to strictly override vendor defaults (bypasses the Debian 12 Include trap).
  • Anti-Lockout: Smart fallback mechanisms to prevent locking yourself out (see Strict Mode below).
  • Firewall Awareness: Automatically configures ufw or firewalld when changing ports.
• Automation:
  • SSH Keys: Imports from GitHub/URL/Paste.
  • Random Port: Generates valid random high ports (20000-60000).
  • Optimization: One-click System Update & TCP BBR.

🚀 Quick Start

Run as root:

curl -fsSL [https://raw.githubusercontent.com/247like/linux-ssh-init-sh/main/init.sh](https://raw.githubusercontent.com/247like/linux-ssh-init-sh/main/init.sh) -o init.sh && chmod +x init.sh && ./init.sh