========================== How to protect an instance ========================== .. _filtron: https://github.com/asciimoo/filtron Searx depens on external search services. To avoid the abuse of these services it is advised to limit the number of requests processed by searx. An application firewall, filtron_ solves exactly this problem. Filtron is just a middleware between your web server (nginx, apache, ...) and searx. filtron & go ============ .. _Go: https://golang.org/ .. _filtron README: https://github.com/asciimoo/filtron/blob/master/README.md Filtron needs Go_ installed. If Go_ is preinstalled, filtron_ is simply installed by ``go get`` package management (see `filtron README`_). If you use filtron as middleware, a more isolated setup is recommended. #. Create a separated user account (``filtron``). #. Download and install Go_ binary in users $HOME (``~filtron``). #. Install filtron with the package management of Go_ (``go get -v -u github.com/asciimoo/filtron``) #. Setup a proper rule configuration :origin:`[ref] ` (``/etc/filtron/rules.json``). #. Setup a systemd service unit :origin:`[ref] ` (``/lib/systemd/system/filtron.service``). To simplify such a installation and the maintenance of; use our script ``utils/filtron.sh``: .. program-output:: ../utils/filtron.sh --help :ellipsis: 0,5 Sample configuration of filtron =============================== An example configuration can be find below. This configuration limits the access of: - scripts or applications (roboagent limit) - webcrawlers (botlimit) - IPs which send too many requests (IP limit) - too many json, csv, etc. requests (rss/json limit) - the same UserAgent of if too many requests (useragent limit) .. code:: json [{ "name":"search request", "filters":[ "Param:q", "Path=^(/|/search)$" ], "interval":"", "limit":"", "subrules":[ { "name":"roboagent limit", "interval":"", "limit":"", "filters":[ "Header:User-Agent=(curl|cURL|Wget|python-requests|Scrapy|FeedFetcher|Go-http-client)" ], "actions":[ { "name":"block", "params":{ "message":"Rate limit exceeded" } } ] }, { "name":"botlimit", "limit":0, "stop":true, "filters":[ "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)" ], "actions":[ { "name":"block", "params":{ "message":"Rate limit exceeded" } } ] }, { "name":"IP limit", "interval":"", "limit":"", "stop":true, "aggregations":[ "Header:X-Forwarded-For" ], "actions":[ { "name":"block", "params":{ "message":"Rate limit exceeded" } } ] }, { "name":"rss/json limit", "interval":"", "limit":"", "stop":true, "filters":[ "Param:format=(csv|json|rss)" ], "actions":[ { "name":"block", "params":{ "message":"Rate limit exceeded" } } ] }, { "name":"useragent limit", "interval":"", "limit":"", "aggregations":[ "Header:User-Agent" ], "actions":[ { "name":"block", "params":{ "message":"Rate limit exceeded" } } ] } ] }] Route request through filtron ============================= Filtron can be started using the following command: .. code:: sh $ filtron -rules rules.json It listens on ``127.0.0.1:4004`` and forwards filtered requests to ``127.0.0.1:8888`` by default. Use it along with ``nginx`` with the following example configuration. .. code:: nginx location / { proxy_set_header Host $http_host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Scheme $scheme; proxy_pass http://127.0.0.1:4004/; } Requests are coming from port 4004 going through filtron and then forwarded to port 8888 where a searx is being run.