51.161.37.205📋 Copy

## IP INTELLIGENCE BRIEFING: 51.161.37.205/32

Date: Current Analysis

Classification: Moderate Risk – High-Abuse Subnet

EXECUTIVE SUMMARY

IP 51.161.37.205 is an OVH-hosted infrastructure address (ASN 16276) with a risk score of 40 (Moderate). The IP is associated with Ahrefs Pte Ltd under customer block OVH-CUST-281059684. While the IP itself shows no known campaign activity or attacker indicators, it resides within a subnet (51.161.37.0/24) classified as "high_abuse" with 64.8% abuse density. The address is listed on 1 of 8 DNSBLs and resolves to proxy-ca005-san205.ahrefs.net with no open services detected.

OWNERSHIP & GEOLOCATION

• Organization: Dmytro, Ahrefs Pte Ltd
• AS Number: 16276 (OVH SAS)
• Country: Canada (Montreal, QC)
• CIDR Block: 51.161.37.0/24
• Registration: OVH hosting infrastructure

NETWORK CLASSIFICATION

THREAT INDICATORS

Observed Signals:

• No Tor exit node activity
• No known attacker reputation
• No spam source classification
• No known campaign associations
• Operator Score: 0.2174 (Minimal)

Control Plane Anomalies:

• Route stability issues detected
• DNSSEC valid
• CAA records present
• 1 DNSBL listing

OBSERVATION HISTORY

23 total observations recorded. Recent activity concentrated in late June 2026 with consistent signal patterns showing minimal threat indicators. No persistent malicious behavior observed. Threat observation count: 1.

NETWORK RELATIONSHIPS

43 relationship entries identified, all pointing to network OVH-CUST-281059684. Strong network-level association within OVH infrastructure. No certificate or hostname correlations beyond Ahrefs domain.

SUBNET NEIGHBORHOOD ANALYSIS

The 51.161.37.0/24 subnet shows elevated abuse density:

• Risk Distribution: 0 high, 99 medium, 1 low risk neighbors
• Abuse Classification: high_abuse
• Threat Concentration: 166 threat siblings out of 256 total

Neighbor sample includes:

• 51.161.37.0 (Risk: 50)
• 51.161.37.1 (Risk: 40)
• 51.161.37.2 (Risk: 40)

SECURITY RECOMMENDATIONS

Immediate Actions:

```bash

# iptables

iptables -A INPUT -s 51.161.37.205 -j DROP

# nftables

nft add rule inet filter input ip saddr 51.161.37.205 drop

# Cloudflare WAF

"ip.src eq 51.161.37.205" → BLOCK

# AWS WAF

Addresses: ["51.161.37.205/32"] → BLOCK

```

Contextual Notes:

• No open ports detected; services appear firewalled
• Consider blocking subnet 51.161.37.0/24 due to high abuse density (64.8%)
• Monitor for correlation with known Ahrefs-related malicious campaigns
• Review DNSBL listing cause for the single blacklist hit

CONCLUSION

IP 51.161.37.205 represents a moderate-risk infrastructure address within a high-abuse OVH subnet. While not directly linked to known malicious activity, the subnet's elevated abuse density warrants defensive blocking. No immediate threat intelligence indicates active exploitation, but network-level controls are recommended given the neighborhood risk profile.

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