51.89.129.1📋 Copy

# IP Intelligence Briefing: 51.89.129.1

Classification: Moderate Risk | Date: 2026-06-21 | Analyst: IPDebrief Intelligence

---

## Executive Summary

IP 51.89.129.1 is a cloud compute infrastructure address operated by OVH SAS (ASN 16276) with moderate risk classification (score 50/100). The IP is associated with Ahrefs Pte Ltd Dmytro and resolves to hostname proxy-uk008-san1.ahrefs.net. While the individual IP shows moderate risk, the parent subnet 51.89.129.0/24 exhibits high abuse density (0.7695), with 197 of 256 total siblings classified as threat-siblings.

---

## Technical Profile

Geolocation: London, England (GB) • Europe/London timezone • Accuracy: 750km radius

Network Infrastructure:

• ASN: 16276 (OVH SAS)
• Infrastructure Type: Cloud Compute / Hosting
• CIDR Block: 51.89.0.0/16
• BGP Prefix: 51.89.0.0/16

DNS Resolution:

• PTR Hostname: proxy-uk008-san1.ahrefs.net
• Forward Resolution: Confirmed (1 record)
• Domain: ahrefs.net
• TLS Certificate: Not detected

Service Status: No open ports detected • Firewall configured / No services exposed

Threat Indicators:

• DNSBL Listings: 2 of 8 total lists (high severity)
• Tor Exit Node: No
• Known Attacker: No
• Spam Source: No
• Abuse Confidence Score: Not applicable

---

## Risk Assessment

Current Risk Score: 50/100 (Moderate Risk)

Subnet Context: The /24 subnet 51.89.129.0/24 shows concerning abuse patterns:

• Abuse Density: 0.7695 (High)
• Threat Siblings: 197/256 (76.95%)
• Classification: High Abuse
• Inherited Risk: 30

Neighborhood Analysis: Of 100 sampled neighbors, risk distribution shows 89 low-risk, 11 medium-risk, and 0 high-risk IPs. Notable neighbor 51.89.129.2 carries matching risk score of 50.

---

## Historical Observations

Total Signals: 21 observations tracked

Recent Activity (2026-06-21):

• Subnet abuse density confirmed at 0.7695
• DNS resolution to ahrefs.net with CAA records present
• Listed on 8 threat feeds with 2 high-severity classifications
• Geo attribution consistent across sources (London, GB)
• ASN AS16276 ovh sas confirmed via AlienVault OTX

Temporal Analysis:

• Ownership changes: 0
• Threat persistence: 0 days
• Not persistently malicious

---

## Relationship Graph

Total Relationships: 36 links identified

Key Connections:

• Multiple Same Network relationships to OVH_282347344 (network-level clustering)
• Strong infrastructure-level association with OVH cloud infrastructure

---

## Recommended Security Actions

Primary Recommendation: Block traffic from 51.89.129.1/32 due to moderate risk score and subnet-level abuse patterns.

Firewall Rules:

• iptables: `iptables -A INPUT -s 51.89.129.1 -j DROP`
• nftables: `nft add rule inet filter input ip saddr 51.89.129.1 drop`
• nginx: `deny 51.89.129.1;`
• pfSense: `51.89.129.1/32`
• Cloudflare WAF: Block with expression `ip.src eq 51.89.129.1`
• AWS WAF: Add `51.89.129.1/32` to block list

Operational Notes:

• No specific service-level recommendations due to firewall configuration
• Consider subnet-level blocking for 51.89.129.0/24 given high abuse density
• Monitor for traffic from related IPs in same network block

---

## Intelligence Conclusions

IP 51.89.129.1 presents moderate individual risk but operates within a high-abuse subnet environment. The association with legitimate hosting provider OVH and Ahrefs infrastructure suggests legitimate use, but the subnet-level abuse indicators warrant defensive posture. SOC teams should evaluate traffic patterns and consider broader subnet-level filtering based on operational risk tolerance.

This summary was generated by AI and may contain inaccuracies. Verify critical details independently.