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==========================
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 $HOME (``~filtron``).
#. Install filtron with the package management of Go_ (``go get -v -u
github.com/asciimoo/filtron``)
#. Setup a proper rule configuration :origin:`[ref]
<utils/templates/etc/filtron/rules.json>` (``/etc/filtron/rules.json``).
#. Setup a systemd service unit :origin:`[ref]
<utils/templates/lib/systemd/system/filtron.service>`
(``/lib/systemd/system/filtron.service``).
To simplify such a installation and the maintenance of; use our script
``utils/filtron.sh``:
.. program-output:: ../utils/filtron.sh --help
:ellipsis: 0,5
Sample configuration of filtron
===============================
An example configuration can be find below. This configuration limits the access
of:
- scripts or applications (roboagent limit)
- webcrawlers (botlimit)
- IPs which send too many requests (IP limit)
- too many json, csv, etc. requests (rss/json limit)
- the same UserAgent of if too many requests (useragent limit)
.. code:: json
[{
"name":"search request",
"filters":[
"Param:q",
"Path=^(/|/search)$"
],
"interval":"<time-interval-in-sec (int)>",
"limit":"<max-request-number-in-interval (int)>",
"subrules":[
{
"name":"roboagent limit",
"interval":"<time-interval-in-sec (int)>",
"limit":"<max-request-number-in-interval (int)>",
"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":"<time-interval-in-sec (int)>",
"limit":"<max-request-number-in-interval (int)>",
"stop":true,
"aggregations":[
"Header:X-Forwarded-For"
],
"actions":[
{
"name":"block",
"params":{
"message":"Rate limit exceeded"
}
}
]
},
{
"name":"rss/json limit",
"interval":"<time-interval-in-sec (int)>",
"limit":"<max-request-number-in-interval (int)>",
"stop":true,
"filters":[
"Param:format=(csv|json|rss)"
],
"actions":[
{
"name":"block",
"params":{
"message":"Rate limit exceeded"
}
}
]
},
{
"name":"useragent limit",
"interval":"<time-interval-in-sec (int)>",
"limit":"<max-request-number-in-interval (int)>",
"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.
|
