sistrix Crawler

seo (sistrix|SISTRIX) [cC]rawler

SISTRIX SEO tool web crawler for analysis

About this crawler

sistrix Crawler is a web crawler identified by the regular-expression pattern (sistrix|SISTRIX) [cC]rawler in the User-Agent request header. It is categorised as seo. Use the regex above to detect, log, allow, or block sistrix Crawler traffic in your web server, CDN edge rules, or robots.txt.

Block-rate · top 25k sites

0.065%
latest snapshot
2026-06-04
matched key: SISTRIX Crawler
2026-05-012026-06-040.21%

Technical details

Name
sistrix Crawler
Pattern
(sistrix|SISTRIX) [cC]rawler
Tags
seo
Reference
https://www.sistrix.com/tutorials/crawling-errors-in-the-optimizer/
Added
2011/08/02
rDNS suffixes
.sistrix.com, .sistrix.net
Instances
1 known sample(s)

rDNS verification (FCrDNS)

Verify a request is genuinely sistrix Crawler with forward-confirmed reverse DNS: the client IP's PTR record must end in one of the suffixes below and a forward A/AAAA lookup of that hostname must return the same IP. UA strings alone are spoofable; FCrDNS is not.

Sample User-Agent strings

Mozilla/5.0 (compatible; SISTRIX Crawler; http://crawler.sistrix.net/)

Block this crawler

robots.txt — disallow sistrix Crawler:

User-agent: sistrix Crawler Disallow: /

Apache .htaccess — return 403:

RewriteEngine On RewriteCond %{HTTP_USER_AGENT} (sistrix|SISTRIX) [cC]rawler [NC] RewriteRule .* - [F,L]

Nginx — return 403 inside a server block:

if ($http_user_agent ~* "(sistrix|SISTRIX) [cC]rawler") { return 403; }
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