51.161.65.138📋 Copy

# IP Intelligence Briefing: 51.161.65.138

Classification: Moderate Risk / Cloud Infrastructure / High-Abuse Neighborhood

Date: 2026-06-25

Analyst: IPDebrief Intelligence Team

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## Executive Summary

IP 51.161.65.138 is a cloud-hosting address in Montreal, Canada, associated with OVH infrastructure and the ahrefs.net domain. The IP carries a moderate risk score (40/100) and resides in a high-abuse-density subnet where 55.5% of siblings exhibit threat indicators. No active services were detected, indicating the host is firewalled.

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## Profile Overview

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## Neighborhood Analysis

Subnet: 51.161.65.0/24

Abuse Density: 0.5547 (High Abuse)

Classification: high_abuse

Sibling Statistics:

• Total Siblings: 256
• Active Siblings: 218
• Threat Siblings: 142 (55.5%)

Risk Distribution: 100 medium-risk neighbors, 0 high-risk, 0 low-risk

The subnet exhibits elevated abuse patterns with a significant concentration of flagged threat IPs. This context suggests the address operates within a shared hosting environment with mixed traffic profiles.

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## Historical Observations

Total Signals: 26 observations recorded

Recent Activity: Consistent high-abuse classification in latest observations

Key temporal indicators:

• Subnet abuse density remained stable at 0.5547
• Network classification consistently identified as cloud/hosting infrastructure
• Geographic validation shows RTT inconsistency (29ms observed vs. 121.6ms minimum expected for Montreal distance)

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## Threat Indicators

No active threat indicators detected. IP is not associated with known campaigns or malicious reputation sources.

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## Infrastructure & DNS

Resolved Hostname: proxy-ca011-san138.ahrefs.net

Domain: ahrefs.net

Email Auth: SPF/DMARC not configured

HTTP Services: None (firewalled)

The hostname suggests this IP may serve as a proxy or internal service endpoint for the ahrefs.net domain. No web services or open ports were detected.

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## Recommended Actions

1. Monitor Contextually: Given the high-abuse neighborhood, monitor for lateral threat patterns in the 51.161.65.0/24 subnet

2. DNS Verification: Verify ahrefs.net DNS resolution from legitimate sources

3. Geographic Validation: Investigate RTT inconsistency (claimed Montreal location with anomalous latency)

4. Allow/Block Decision: Risk score of 40 permits traffic flow if legitimate ahrefs.net traffic is expected; otherwise, consider blocking if no business justification exists

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Status: No immediate threat indicators. Elevated neighborhood risk warrants contextual monitoring.

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