Nginx config

domain_main.conf

server {
  listen 80;
  server_name main_domain.com www.main_domain.com;
  return 301 https://$server_name$request_uri;
}

server {
	listen 443 ssl default_server;

	# access_log off;
	access_log /home/main_domain.com/logs/access.log;
	# error_log off;
	error_log /home/main_domain.com/logs/error.log;

	root /var/www/main_domain.com/public_html;
	index index.js index.html index.htm;
	server_name main_domain.com www.main_domain.com;
	
	# SSL
	ssl_certificate /etc/letsencrypt/live/main_domain.com/fullchain.pem;
	ssl_certificate_key /etc/letsencrypt/live/main_domain.com/privkey.pem;
	ssl_protocols TLSv1 TLSv1.1 TLSv1.2; 
	ssl_prefer_server_ciphers on; 
	ssl_ciphers EECDH+CHACHA20:EECDH+AES128:RSA+AES128:EECDH+AES256:RSA+AES256:EECDH+3DES:RSA+3DES:!MD5;

	# Improve HTTPS performance with session resumption
	ssl_session_cache shared:SSL:50m;
	ssl_session_timeout 1d;

	# DH parameters
	ssl_dhparam /etc/nginx/ssl/dhparam.pem;
	# Enable HSTS
	add_header Strict-Transport-Security "max-age=31536000" always;

	location / {
		proxy_http_version 1.1;
		proxy_set_header Upgrade $http_upgrade;
		proxy_set_header Connection 'upgrade';
		proxy_set_header X-Real-IP $remote_addr;  # This line.
		proxy_set_header Host $host;
		proxy_cache_bypass $http_upgrade;
		proxy_connect_timeout   1000;
		proxy_send_timeout      1500;
		proxy_read_timeout      2000;

		try_files $uri $uri/ index.html;
	}
}

nginx.config

user  nginx;
worker_processes  1;
error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    include    /etc/nginx/proxy.conf;
    include    /etc/nginx/fastcgi.conf;

    default_type  application/octet-stream;

    log_format main      '$remote_addr - $remote_user [$time_local]  '
        '"$request" $status $bytes_sent '
        '"$http_referer" "$http_user_agent" '
        '"$gzip_ratio"';

    log_format download  '$remote_addr - $remote_user [$time_local]  '
        '"$request" $status $bytes_sent '
        '"$http_referer" "$http_user_agent" '
        '"$http_range" "$sent_http_content_range"';

    ##
    # Logging Settings
    ##
    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    client_header_timeout  3m;
    client_body_timeout    3m;
    send_timeout           3m;


    client_header_buffer_size    1k;
    large_client_header_buffers  4 4k;

    gzip on;
    gzip_disable "msie6";
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_buffers 16 8k;
    gzip_http_version 1.1;
    gzip_types application/javascript application/rss+xml application/vnd.ms-fontobject application/x-font application/x-font-opentype application/x-font-otf application/x-font-truetype application/x-font-ttf application/x-javascript application/xhtml+xml application/xml font/opentype font/otf font/ttf image/svg+xml image/x-icon text/css text/javascript text/plain text/xml;

    output_buffers   1 32k;
    postpone_output  1460;

    sendfile         on;
    tcp_nopush       on;

    tcp_nodelay      on;

    keepalive_timeout  75 20;

    fastcgi_buffers         8 16k;
    fastcgi_buffer_size     32k;
    fastcgi_connect_timeout 300;
    fastcgi_send_timeout    300;
    fastcgi_read_timeout    300;

    include /etc/nginx/conf.d/*.conf;
}

orther_domain.conf

server {
	listen 443 ssl;
	server_name other_domain.com www.other_domain.com;

	# access_log off;
	access_log /home/other_domain.com/logs/access.log;
	# error_log off;
	error_log /home/other_domain.com/logs/error.log;


	# SSL
	ssl_certificate /etc/letsencrypt/live/other_domain.com/fullchain.pem;
	ssl_certificate_key /etc/letsencrypt/live/other_domain.com/privkey.pem;
	ssl_protocols TLSv1 TLSv1.1 TLSv1.2; 
	ssl_prefer_server_ciphers on; 
	ssl_ciphers EECDH+CHACHA20:EECDH+AES128:RSA+AES128:EECDH+AES256:RSA+AES256:EECDH+3DES:RSA+3DES:!MD5;

	# Improve HTTPS performance with session resumption
	ssl_session_cache shared:SSL:50m;
	ssl_session_timeout 1d;

	# DH parameters
	ssl_dhparam /etc/nginx/ssl/dhparam.pem;
	# Enable HSTS
	add_header Strict-Transport-Security "max-age=31536000" always;

    location /
    {
		proxy_pass http://localhost:[PORT];
		proxy_http_version 1.1;
		proxy_set_header Upgrade $http_upgrade;
		proxy_set_header Connection 'upgrade';
		proxy_set_header X-Real-IP $remote_addr;  # This line.
		proxy_set_header Host $host;
		proxy_cache_bypass $http_upgrade;
		proxy_connect_timeout   1000;
		proxy_send_timeout      1500;
		proxy_read_timeout      2000;
    }
}