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AbuseIPDB » 51.81.103.251

51.81.103.251 was found in our database!

This IP was reported 35 times. Confidence of Abuse is 0%: ?

ISP	OVH US LLC
Usage Type	Data Center/Web Hosting/Transit
ASN	AS16276
Hostname(s)	proxy-us-east000-cip12.ahrefs.net
Domain Name	ovhcloud.com
Country	🇺🇸 United States of America
City	Leesburg, Virginia

IP info including ISP, Usage Type, and Location provided by IPInfo. Updated weekly.

Important Note: 51.81.103.251 is an IP address from within our whitelist belonging to the subnet 51.81.103.240/28, 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.

Report 51.81.103.251

Whois 51.81.103.251

IP Abuse Reports for 51.81.103.251:

This IP address has been reported a total of 35 times from 15 distinct sources. 51.81.103.251 was first reported on August 23rd 2026, and the most recent report was 13 hours ago.

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.

Reporter	IoA Timestamp (UTC)	Comment	Categories
🇨🇦 Mediashaker	2026-09-19 07:02:41 (13 hours ago)	(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/Un ... show more (apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/United States/proxy-us-east000-cip12.ahrefs.net) show less	Bad Web Bot
🇺🇸 TPI-Abuse	2026-09-18 12:20:32 (1 day ago)	(mod_security) mod_security (id:210492) triggered by 51.81.103.251 (proxy-us-east000-cip12.ahrefs.ne ... show more (mod_security) mod_security (id:210492) triggered by 51.81.103.251 (proxy-us-east000-cip12.ahrefs.net): 1 in the last 300 secs; Ports: *; Direction: 1; Trigger: LF_MODSEC; Logs: [Fri Sep 18 08:20:24.344126 2026] [security2:error] [pid 8607:tid 8607] [client 51.81.103.251:41048] ModSecurity: Access denied with code 403 (phase 1). Matched phrase ".htaccess" at REQUEST_URI. [file "/etc/apache2/conf.d/modsec_vendor_configs/comodo_apache/02_Global_Generic.conf"] [line "117"] [id "210492"] [rev "3"] [severity "CRITICAL"] [tag "CWAF"] [tag "Generic"] [hostname "www.archief.org"] [uri "/bak.htaccess"] [unique_id "aq0siMOmqOUG_qjwLoUEnQAAAA0"] show less	Brute-Force Bad Web Bot Web App Attack
🇩🇪 palzer.IT	2026-09-16 17:15:03 (3 days ago)	Fail2ban automatic report for plesk-apache-badbot: 51.81.103.251 - - [10/Sep/2026:06:26:27 +0200] GE ... show more Fail2ban automatic report for plesk-apache-badbot: 51.81.103.251 - - [10/Sep/2026:06:26:27 +0200] GET /badminton-archiv/95-ausschreibung-hobbyturnier-2017?rCH=-2 [DOMAIN_REMOVED] 301 5974 - Mozilla/5.0 (compatible; AhrefsBot/7.0; +[DOMAIN_REMOVED] show less	Bad Web Bot
🇺🇸 SX Communications	2026-09-16 09:14:38 (3 days ago)	Blocked abusive HTTP application-layer DoS / botnet traffic from 51.81.103.251: traffic from this ad ... show more Blocked abusive HTTP application-layer DoS / botnet traffic from 51.81.103.251: 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	DDoS Attack Bad Web Bot Exploited Host
🇩🇪 rh24	2026-09-15 21:50:54 (3 days ago)	(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/Un ... show more (apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/United States/proxy-us-east000-cip12.ahrefs.net) show less	Bad Web Bot
🇺🇸 SX Communications	2026-09-14 17:53:21 (5 days ago)	Blocked abusive HTTP application-layer DoS / botnet traffic from 51.81.103.251: traffic from this ad ... show more Blocked abusive HTTP application-layer DoS / botnet traffic from 51.81.103.251: 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	DDoS Attack Bad Web Bot Exploited Host
🇬🇧 cg-design.co.uk	2026-09-14 17:11:48 (5 days ago)	(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/Un ... show more (apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/United States/proxy-us-east000-cip12.ahrefs.net) show less	Bad Web Bot
🇨🇦 Mediashaker	2026-09-13 12:48:59 (6 days ago)	(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/Un ... show more (apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/United States/proxy-us-east000-cip12.ahrefs.net) show less	Bad Web Bot
🇺🇸 SX Communications	2026-09-13 11:54:28 (6 days ago)	Blocked abusive HTTP application-layer DoS / botnet traffic from 51.81.103.251: traffic from this ad ... show more Blocked abusive HTTP application-layer DoS / botnet traffic from 51.81.103.251: 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	DDoS Attack Bad Web Bot Exploited Host
🇨🇦 Mediashaker	2026-09-11 17:32:01 (1 week ago)	(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/Un ... show more (apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/United States/proxy-us-east000-cip12.ahrefs.net) show less	Bad Web Bot
🇩🇪 rh24	2026-09-11 05:11:09 (1 week ago)	(apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/Un ... show more (apache-useragents) Failed apache-useragents trigger with match [redacted] from 51.81.103.251 (US/United States/proxy-us-east000-cip12.ahrefs.net) show less	Bad Web Bot
🇩🇪 palzer.IT	2026-09-11 04:35:50 (1 week ago)	Fail2ban automatic report for plesk-apache-badbot: 51.81.103.251 - - [10/Sep/2026:06:26:27 +0200] GE ... show more Fail2ban automatic report for plesk-apache-badbot: 51.81.103.251 - - [10/Sep/2026:06:26:27 +0200] GET /badminton-archiv/95-ausschreibung-hobbyturnier-2017?rCH=-2 [DOMAIN_REMOVED] 301 5974 - Mozilla/5.0 (compatible; AhrefsBot/7.0; +[DOMAIN_REMOVED] show less	Bad Web Bot
🇩🇪 palzer.IT	2026-09-10 04:26:44 (1 week ago)	Fail2ban automatic report for plesk-apache-badbot: 51.81.103.251 - - [10/Sep/2026:06:26:27 +0200] GE ... show more Fail2ban automatic report for plesk-apache-badbot: 51.81.103.251 - - [10/Sep/2026:06:26:27 +0200] GET /badminton-archiv/95-ausschreibung-hobbyturnier-2017?rCH=-2 [DOMAIN_REMOVED] 301 5974 - Mozilla/5.0 (compatible; AhrefsBot/7.0; +[DOMAIN_REMOVED] show less	Bad Web Bot
🇺🇸 TPI-Abuse	2026-09-09 01:22:30 (1 week ago)	(mod_security) mod_security (id:210730) triggered by 51.81.103.251 (proxy-us-east000-cip12.ahrefs.ne ... show more (mod_security) mod_security (id:210730) triggered by 51.81.103.251 (proxy-us-east000-cip12.ahrefs.net): 1 in the last 300 secs; Ports: *; Direction: 1; Trigger: LF_MODSEC; Logs: [Tue Sep 08 21:22:26.260226 2026] [security2:error] [pid 21117:tid 21134] [client 51.81.103.251:27438] ModSecurity: Access denied with code 403 (phase 2). Match of "pmFromFile userdata_wl_extensions" against "TX:extension" required. [file "/etc/apache2/conf.d/modsec_vendor_configs/comodo_apache/10_HTTP_HTTP.conf"] [line "27"] [id "210730"] [rev "5"] [msg "COMODO WAF: URL file extension is restricted by policy\|\|piazza9.com\|F\|2"] [data ".butterbell.com"] [severity "CRITICAL"] [tag "CWAF"] [tag "HTTP"] [hostname "piazza9.com"] [uri "/dpiazzadesign.com/www.butterbell.com"] [unique_id "aqC00iTIBKiFJeXkFNs19wAAAI8"] show less	Brute-Force Bad Web Bot Web App Attack
🇩🇪 ghostwarriors	2026-09-08 00:20:16 (1 week ago)	Webpage scraping	Brute-Force Bad Web Bot Web App Attack

Showing 1 to 15 of 35 reports

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