Set up ssl proxy with nginx and letsencrypt (https://secure.example.com => http://example.com)

nginx-config.conf

# SSL server config
server {
        listen 443 ssl;

        server_name secure.example.com;

        ssl_certificate /etc/letsencrypt/live/secure.example.com/fullchain.pem;
        ssl_certificate_key /etc/letsencrypt/live/secure.example.com/privkey.pem;
        
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_prefer_server_ciphers on;
        ssl_dhparam /etc/ssl/certs/dhparam.pem;
        ssl_ciphers 'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA';
        ssl_session_timeout 1d;
        ssl_session_cache shared:SSL:50m;
        ssl_stapling on;
        ssl_stapling_verify on;
        add_header Strict-Transport-Security max-age=15768000;
        
        location / {

                proxy_set_header        Host $host;
                proxy_set_header        X-Real-IP $remote_addr;
                proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header        X-Forwarded-Proto $scheme;

                proxy_pass          http://example.com;
                proxy_read_timeout  90;
        }
}

# Redirect http to https
server {
    listen 80;
    server_name example.com www.example.com;
    return 301 https://$host$request_uri;
}

setup.sh

# Update & upgrade
sudo apt-get update
sudo apt-get upgrade

# Install & start nginx
sudo apt-get install nginx -y
sudo service nginx start

# Install git
sudo apt-get install git -y

# Install letsencrypt
git clone https://github.com/letsencrypt/letsencrypt
cd letsencrypt

# Install letsencrypt dependencies
./letsencrypt-auto --help all

# Stop nginx (port 80 needed by letsencrypt)
sudo nginx service stop

# Generate certificate
./letsencrypt-auto certonly --rsa-key-size 4096

# Generate a strong Diffie-Hellman (2048-bit) group
sudo openssl dhparam -out /etc/ssl/certs/dhparam.pem 2048

# Config nginx to use certificate (see nginx-config.conf)
sudo vim /etc/nginx/sites-available/default

# Reload nginx
sudo service nginx reload