Normalize reST sources with best practice and KISS in mind. to name a few points: - simplify reST tables - make use of ``literal`` markup for monospace rendering - fix code-blocks for better rendering in HTML - normalize section header markup - limit all lines to a maximum of 79 characters - add option -H to the sudo command used in code blocks - drop useless indentation of lists - ... [1] https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
		
			
				
	
	
		
			149 lines
		
	
	
		
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			149 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			ReStructuredText
		
	
	
	
	
	
==========================
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How to protect an instance
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==========================
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Searx depens on external search services.  To avoid the abuse of these services
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it is advised to limit the number of requests processed by searx.
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An application firewall, ``filtron`` solves exactly this problem.  Information
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on how to install it can be found at the `project page of filtron
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<https://github.com/asciimoo/filtron>`__.
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Sample configuration of filtron
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===============================
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An example configuration can be find below. This configuration limits the access
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of:
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- scripts or applications (roboagent limit)
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- webcrawlers (botlimit)
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- IPs which send too many requests (IP limit)
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- too many json, csv, etc. requests (rss/json limit)
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- the same UserAgent of if too many requests (useragent limit)
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.. code:: json
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   [{
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      "name":"search request",
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      "filters":[
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         "Param:q",
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         "Path=^(/|/search)$"
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      ],
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      "interval":"<time-interval-in-sec (int)>",
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      "limit":"<max-request-number-in-interval (int)>",
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      "subrules":[
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         {
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            "name":"roboagent limit",
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            "interval":"<time-interval-in-sec (int)>",
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            "limit":"<max-request-number-in-interval (int)>",
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            "filters":[
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               "Header:User-Agent=(curl|cURL|Wget|python-requests|Scrapy|FeedFetcher|Go-http-client)"
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            ],
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            "actions":[
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               {
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                  "name":"block",
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                  "params":{
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                     "message":"Rate limit exceeded"
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                  }
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               }
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            ]
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         },
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         {
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            "name":"botlimit",
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            "limit":0,
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            "stop":true,
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            "filters":[
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               "Header:User-Agent=(Googlebot|bingbot|Baiduspider|yacybot|YandexMobileBot|YandexBot|Yahoo! Slurp|MJ12bot|AhrefsBot|archive.org_bot|msnbot|MJ12bot|SeznamBot|linkdexbot|Netvibes|SMTBot|zgrab|James BOT)"
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            ],
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            "actions":[
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               {
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                  "name":"block",
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                  "params":{
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                     "message":"Rate limit exceeded"
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                  }
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               }
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            ]
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         },
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         {
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            "name":"IP limit",
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            "interval":"<time-interval-in-sec (int)>",
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            "limit":"<max-request-number-in-interval (int)>",
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            "stop":true,
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            "aggregations":[
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               "Header:X-Forwarded-For"
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            ],
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            "actions":[
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               {
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                  "name":"block",
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                  "params":{
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                     "message":"Rate limit exceeded"
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                  }
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               }
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            ]
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         },
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         {
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            "name":"rss/json limit",
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            "interval":"<time-interval-in-sec (int)>",
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            "limit":"<max-request-number-in-interval (int)>",
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            "stop":true,
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            "filters":[
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               "Param:format=(csv|json|rss)"
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            ],
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            "actions":[
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               {
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                  "name":"block",
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                  "params":{
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                     "message":"Rate limit exceeded"
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                  }
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               }
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            ]
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         },
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         {
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            "name":"useragent limit",
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            "interval":"<time-interval-in-sec (int)>",
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            "limit":"<max-request-number-in-interval (int)>",
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            "aggregations":[
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               "Header:User-Agent"
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            ],
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            "actions":[
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               {
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                  "name":"block",
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                  "params":{
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                     "message":"Rate limit exceeded"
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                  }
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               }
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            ]
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         }
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      ]
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   }]
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Route request through filtron
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=============================
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Filtron can be started using the following command:
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.. code:: sh
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   $ filtron -rules rules.json
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It listens on ``127.0.0.1:4004`` and forwards filtered requests to
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``127.0.0.1:8888`` by default.
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Use it along with ``nginx`` with the following example configuration.
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.. code:: nginx
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   location / {
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        proxy_set_header   Host    $http_host;
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        proxy_set_header   X-Real-IP $remote_addr;
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        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
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        proxy_set_header   X-Scheme $scheme;
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        proxy_pass         http://127.0.0.1:4004/;
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   }
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Requests are coming from port 4004 going through filtron and then forwarded to
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port 8888 where a searx is being run.
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