user www-data;
worker_processes auto; # Lets Nginx determine the number of cores available, disks, server load, and network subsystem
worker_rlimit_nofile 20960; # Limit on the maximum number of open files for worker processes.
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
    worker_connections 1024; # Number of simultaneous connections that can be opened by a worker. Default is 512
    multi_accept on; # Allows a worker to accept many connections in the queue at a time
    use epoll; # Uses epoll as method to process a connection from the client
    epoll_events 512; # Number of events Nginx will transfer to the kernel
}

http {

    ##
    # Headers
    ##

    add_header X-Frame-Options SAMEORIGIN; # Blocks the browser from rendering the page inside an frame or iframe, unless it's from the same domain
    add_header X-XSS-Protection "1; mode=block"; # Forces browser to use XSS filter

    ##
    # Basic Settings
    ##

    sendfile on;
    tcp_nopush  on; # Allows all data to be sent at once
    tcp_nodelay on; # Adds packets to each other and sends them all at once
    keepalive_timeout 30s; # Keep connections alive for about 30 seconds. The default is 65 seconds. Reduced time to avoide wasting resources
    keepalive_requests 30; # Number of requests to keep alive for a specific period of time.  20 or 30
    send_timeout 30s; # Sets a timeout for transmitting data to the client
    types_hash_max_size 4096;
    charset utf-8;
    server_tokens off; # Disables sending Nginx version number in error pages and server header

    server_names_hash_bucket_size 64;
    # server_name_in_redirect off;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    ##
    # SSL Settings
    ##

    ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
    ssl_prefer_server_ciphers on;

    ##
    # Logging Settings
    ##

    access_log /var/log/nginx/access.log combined; # Logs accesses to access.log using the combined format
    error_log /var/log/nginx/error.log warn; # Logs errors to warn.log using the warn format

    ##
    # Gzip Settings
    ##

    gzip on; # Enables Gzip
    gzip_vary on; # Adds header field Vary:Accept Encoding to the response
    gzip_proxied any; # Enables compression for all proxied requests
    gzip_comp_level 2; # Compression level, between 1 - 9 (the higher, the more resource-consuming)
    gzip_buffers 16 8k; # Number and size of buffers used to compress a response
    gzip_http_version 1.1; # Minimum HTTP version of a request for a compressed response
    gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript; # File types affected by the compression
    gzip_min_length 1000; # Minimum response length

    ##
    # Cache Settings
    ##

    open_file_cache max=1000 inactive=30s; # Maximum number of elements in the cache, and time after which an element is removed from the cache if it has not been accessed during this time; by default, it is 60 seconds
    open_file_cache_valid 30s; # Valid period after which the information related to files and directories is re-validated again
    open_file_cache_min_uses 4; # Minimum number of file accesses during the period configured by the inactive parameter of the open_file_cache directive, required for a file descriptor to remain open in the cache.
    open_file_cache_errors on; # Enables caching of errors

    ##
    # Virtual Host Configs
    ##

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;

    ##
    # Default Server Settings For Invalid Domains
    ##

    server {
        # The default_server option should only be present in this configuration file
        listen 80 default_server;
        listen [::]:80 default_server;

        # Matches any invalid domain or the server's IP
        server_name  _;

        # Closes connection with no response if attempted to connect to the above
        return 444;
    }
}

# mail {
#    # See sample authentication script at:
#    # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript

#    # auth_http localhost/auth.php;
#    # pop3_capabilities "TOP" "USER";
#    # imap_capabilities "IMAP4rev1" "UIDPLUS";

#    server {
#        listen     localhost:110;
#        protocol   pop3;
#        proxy      on;
#    }

#    server {
#        listen     localhost:143;
#        protocol   imap;
#        proxy      on;
#    }
# }