====== Nginx ======

====== Performance ======

  * uninstall nginx-full (nginx is just an empty meta-package), instead install nginx-extras from dotdeb. this version includes pagespeed and everything
  * try nginx-light -> it's faster (ca. 0,2sec), but few modules
  * always use latest versions from dotdeb repo

**nginx.conf optimizations:**
**
  # use the number of** logical cores / threads:
  worker_processes 8;
  worker_connections 1024;

  multi_accept on; 
  
  # log buffer (reduce slow disc writes)
  access_log /var/log/nginx/access.log main buffer=16k;

  # gzip config
  gzip on;
  gzip_disable "msie6";
  gzip_min_length 1400;
  gzip_vary on;
  gzip_proxied any;
  gzip_comp_level 6;
  gzip_buffers 16 8k;
  gzip_http_version 1.1;
  gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

  # Cache information about frequently accessed files
  open_file_cache max=2000 inactive=20s;
  open_file_cache_valid 60s;
  open_file_cache_min_uses 5;
  open_file_cache_errors off;

  # buffers optimzed:
  client_max_body_size 20m;
  client_body_buffer_size 128k;
  # fix 169 upstream sent too big header while reading response header from upstream
  proxy_buffer_size   128k;
  proxy_buffers   4 256k;
  proxy_busy_buffers_size   256k;
  proxy_connect_timeout  1200s;
  proxy_send_timeout  1200s;
  proxy_read_timeout  1200s;
  fastcgi_send_timeout 1200s;
  fastcgi_read_timeout 1200s;
  
  # mitigate https://httpoxy.org:
  fastcgi_param HTTP_PROXY "";


  tcp_nopush on;
  tcp_nodelay on;
  #tcp_nopush off;	 # -> 0,1s - 0,3s slower
  keepalive_timeout 5;   # instead of 65 - less ressources, same performance


===== mod_pagespeed =====

dotdeb packages include mod_pagespeed for nginx in wheezy

**add dotdeb repos to /etc/apt/sources.list:**
  deb http://packages.dotdeb.org wheezy all
  deb-src http://packages.dotdeb.org wheezy all
**
update and install nginx-extras from dotdeb:**
  apt-get update
  apt-get install nginx-extras


**create cache dir:**
  mkdir /var/cache/ngx_pagespeed/
  chown www-data:www-data /var/cache/ngx_pagespeed/

**edit /etc/nginx/sites-available/default:**

  server {
    #....
    
    pagespeed on;
    pagespeed RewriteLevel CoreFilters;
    pagespeed FileCachePath "/var/cache/ngx_pagespeed/";
    pagespeed EnableFilters combine_css,combine_javascript,remove_comments,collapse_whitespace;
    
    #....
  }

**play with the filters:**

https://developers.google.com/speed/pagespeed/module/config_filters


===== rewrites =====

URL-Encoding with Umlauten is a problem. Here is howto fix it:

  rewrite (*UTF8)^/[öüäÖÜÄßa-zA-Z][a-zA-Z]/index.php(.*)$ /index.php$1;


===== microcaching =====

Cache PHP output for a very short time on busy sites to reduce php load:

Vhost config top:

  fastcgi_cache_path /home/cache levels=1:2 keys_zone=MYAPP:100m inactive=60m;
  fastcgi_cache_key "$scheme$request_method$host$request_uri";


server {
  ....
  
  location ~ \.php$ {

  # Setup var defaults
  set $no_cache "";
  # If non GET/HEAD, don't cache & mark user as uncacheable for 1 second via cookie
  if ($request_method !~ ^(GET|HEAD)$) {
       set $no_cache "1";
  }
  # Drop no cache cookie if need be
  # (for some reason, add_header fails if included in prior if-block)
  if ($no_cache = "1") {
       add_header Set-Cookie "_mcnc=1; Max-Age=2; Path=/";
       add_header X-Microcachable "0";
  }
  # Bypass cache if no-cache cookie is set
  if ($http_cookie ~* "_mcnc") {
       set $no_cache "1";
  }
  # Bypass cache if flag is set
  fastcgi_no_cache $no_cache;
  fastcgi_cache_bypass $no_cache;
  fastcgi_cache microcache;
  fastcgi_cache_key $server_name|$request_uri;
  fastcgi_cache_valid 404 30m;
  fastcgi_cache_valid 200 10s;
  fastcgi_max_temp_file_size 1M;
  fastcgi_cache_use_stale updating;
  fastcgi_pass_header Set-Cookie;
  fastcgi_pass_header Cookie;
  fastcgi_ignore_headers Cache-Control Expires Set-Cookie;

====== Security ======


===== Block Bots, SQL Injections, etc =====

Howto Block Bots in nginx.conf or included config. Here's an extensive List:

  server { ...
  
    if ($http_user_agent ~* (AspiegelBot|MegaIndex|heritrix|panscient|HubSpot|libwww-perl|OpenVAS-VT|masscan|Linguee|Nimbostratus|Seekport|SMTBot|SEOkicks|SeobilityBot|360Spider|AhrefsBot|BLEXBot|MJ12bot|BUbiNG|Findxbot|Morfeus|larbin|ZmEu|Toata|talktalk|Baiduspider|webalta|nikto|wkito|pikto|scan|acunetix|morfeus|webcollage|youdao|HTTrack|clshttp|archiver|loader|email|harvest|extract|grab|miner|SemrushBot|GetWeb!|GetRight|Go!Zilla|Download\Demon|Go-Ahead-Got-It|TurnitinBot|GrabNet|Indy\ Library) ) {
    
        # Connection Closed Without Response
        # A non-standard status code used to instruct nginx to close the connection without sending a response to the client, 
        # most commonly used to deny malicious or malformed requests.
        
        return 444;
    }
  ...
  }



https://www.howtoforge.com/nginx-how-to-block-exploits-sql-injections-file-injections-spam-user-agents-etc