IP info including ISP, Usage Type, and Location provided
by IPInfo. Updated weekly.
Important Note: 51.81.104.40 is an IP address from within
our whitelist belonging to the subnet
51.81.104.32/28,
which we identify as: "Ahrefs Crawler".
Whitelisted netblocks are typically owned by trusted entities, such as Google
or Microsoft who may use them for search engine spiders. However, these same entities
sometimes also provide cloud servers and mail services which are easily abused. Pay special
attention when trusting or distrusting these IPs.
This IP address has been reported a total of
14
times from
10 distinct
sources.
51.81.104.40 was first reported on
, and the most recent report was
.
Recent Reports:
We have received reports of abusive activity from this IP address within the last week. It is
potentially still actively engaged in abusive activities.
Blocked abusive HTTP application-layer DoS / botnet traffic from 51.81.104.40: traffic from this add ...
show moreBlocked abusive HTTP application-layer DoS / botnet traffic from 51.81.104.40: traffic from this address continues high-cost dynamic page and feed requests at abusive rates via TCP/HTTPS despite edge block responses. Likely compromised end-user host.
show less
(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.104.40 (US/Uni ...
show more(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.104.40 (US/United States/proxy-us-east001-cip9.ahrefs.net)
show less
(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.104.40 (US/Uni ...
show more(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.104.40 (US/United States/proxy-us-east001-cip9.ahrefs.net)
show less
(PERMBLOCK) 51.81.104.40 (US/United States/proxy-us-east001-cip9.ahrefs.net) has had more than 2 tem ...
show more(PERMBLOCK) 51.81.104.40 (US/United States/proxy-us-east001-cip9.ahrefs.net) has had more than 2 temp blocks in the last 604800 secs; Ports: *; Direction: inout; Trigger: LF_PERMBLOCK_COUNT; Logs:
show less
[TueAug2510:14:31.0801932026][security2:error][pid2217246:tid2217268][client51.81.104.40:0]ModSecuri ...
show more[TueAug2510:14:31.0801932026][security2:error][pid2217246:tid2217268][client51.81.104.40:0]ModSecurity:Accessdeniedwithcode403\(phase1\).Stringmatch\"/wp-content/plugins/blog-manager-light/\"atREQUEST_URI.[file\"/etc/apache2/conf.d/modsec_custom_rules.conf\"][line\"367\"][id\"1101011\"][hostname\"alessandrolucchini.ch\"][uri\"/wp-content/plugins/blog-manager-light/frontend/css/default.css\"][unique_id\"ao1O56GmGOl0ZIHbCgdWRgAAAAs\"]
show less
(bot_qv) Bot Scraping QuickView 51.81.104.40 (US/United States/proxy-us-east001-cip9.ahrefs.net): 1 ...
show more(bot_qv) Bot Scraping QuickView 51.81.104.40 (US/United States/proxy-us-east001-cip9.ahrefs.net): 1 in the last 4600 secs; Ports: *; Direction: inout; Trigger: LF_CUSTOMTRIGGER; Logs: 51.81.104.40 - - [24/Aug/2026:20:38:46 +0300] "GET /index.php?dispatch=products.quick_view&product_id=11974&prev_url=index.php%3Fdispatch%3Dcategories.view%26category_id%3D12%26page%3D3&n_items=11307%2C11305%2C11289%2C12414%2C12596%2C11881%2C11882%2C11974%2C11944%2C11950%2C11951%2C11960%2C11969%2C11978%2C11971%2C11306%2C11326%2C11312%2C11323%2C11300 HTTP/2.0" 302 0 "-" "Mozilla/5.0 (compatible; AhrefsBot/7.0; +http://ahrefs.com/robot/)"
show less
Port Scan
Anonymous
Automated web probe/scanner blocked at the edge (WorldTree fleet). Signature: scanner_ua. Example re ...
show moreAutomated web probe/scanner blocked at the edge (WorldTree fleet). Signature: scanner_ua. Example request: /articles/silent-reading-loud-learning-teaching-library-etiquette-for-a-better-classroom/ on teacher-tea.com
show less