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LET'S ENCRYPT - INSTALLATION
Install Certbot and configure Let's Encrypt SSL certificate tool

Category: Certificate · Type: cheatsheet
Official docs: https://letsencrypt.org/

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## What is Let's Encrypt?

**Let's Encrypt** is a free, automated, and open certificate authority that provides SSL/TLS certificates to enable HTTPS on websites. This guide covers installing Certbot, the recommended client for Let's Encrypt.

**⚡ Key Features**
- Free SSL/TLS certificates
- Automated issuance and renewal
- 90-day certificate validity
- Wildcard certificate support
- Cross-platform compatibility

**🎯 Use Cases**
- HTTPS website security
- Production server setup
- Automated SSL renewal
- Multi-domain certificates
- Development and testing

---

## 📥 Certbot - Install Ubuntu

Install Certbot with NGINX plugin on Ubuntu/Debian.

```bash
sudo apt update
sudo apt install certbot python3-certbot-nginx
```

## 📥 Certbot - Install RHEL

Install Certbot on RHEL/CentOS/Rocky Linux.

```bash
sudo dnf install certbot python3-certbot-nginx
```

## 📥 Certbot - Install Apache Plugin

Install Apache plugin instead of NGINX.

```bash
sudo apt install python3-certbot-apache
```

## 📥 Certbot - Install Fedora

Install on Fedora Linux.

```bash
sudo dnf install certbot python3-certbot-nginx
```

## 📥 Certbot - Install Arch

Install on Arch Linux.

```bash
sudo pacman -S certbot certbot-nginx
```

## 📦 Certbot - Snap Installation

Install using Snap (works on most Linux distributions).

```bash
# Remove old certbot
sudo apt remove certbot

# Install snap
sudo snap install core
sudo snap refresh core

# Install certbot
sudo snap install --classic certbot

# Link command
sudo ln -s /snap/bin/certbot /usr/bin/certbot
```

## ✅ Verify Installation

Check Certbot is installed correctly.

```bash
certbot --version
```

## 🔌 List Available Plugins

View installed Certbot plugins.

```bash
certbot plugins
```

Expected output:
```
* nginx
  Description: Nginx Web Server plugin
* standalone
  Description: Standalone Authenticator
* webroot
  Description: Webroot Authenticator
```

## 🔧 First Time Setup

Verify everything is ready for certificate issuance.

```bash
# Check Certbot
certbot --version

# Check web server
sudo systemctl status nginx
# or
sudo systemctl status apache2

# Check port 80 is open
sudo netstat -tlnp | grep :80

# Check port 443 is open
sudo netstat -tlnp | grep :443
```

## 🔥 Firewall Configuration

Ensure firewall allows HTTP and HTTPS.

### UFW (Ubuntu)

```bash
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
sudo ufw status
```

### Firewalld (RHEL/CentOS)

```bash
sudo firewall-cmd --permanent --add-service=http
sudo firewall-cmd --permanent --add-service=https
sudo firewall-cmd --reload
```

### iptables

```bash
sudo iptables -A INPUT -p tcp --dport 80 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 443 -j ACCEPT
sudo service iptables save
```

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