51.161.65.42📋 Copy

# IP Intelligence Briefing: 51.161.65.42

## Executive Summary

IP address 51.161.65.42 is assigned to OVH infrastructure (ASN 16276) and is associated with the organization "Dmytro, Ahrefs Pte Ltd." The IP demonstrates moderate risk posture (risk score 40) with no open services detected. The IP is hosted within the 51.161.65.0/24 subnet, which exhibits high abuse density (0.6094) with 156 of 256 total sibling IPs classified as threat sources.

## Technical Profile

Ownership & Infrastructure

• ASN: 16276 (OVH)
• Organization: Dmytro, Ahrefs Pte Ltd
• Network Block: 51.161.65.0/24
• Infrastructure Type: CloudCompute, Hosting
• Geolocation: Singapore (primary consensus), CA (secondary)

Network Classification

• Cloud Provider: Yes (OVH)
• Hosting Service: Yes
• CDN: No
• Proxy/VPN/Tor: No
• Bogon: No
• Anycast: No

DNS & Services

• PTR Hostname: proxy-ca011-san42.ahrefs.net
• Domain: ahrefs.net
• Forward Resolution: 1 hostname
• Open Ports: None detected
• HTTP Services: No active services
• TLS Certificates: None

Control Plane Signals

• BGP Prefix: 51.161.0.0/17
• Route Stability: False
• DNSSEC Valid: Yes
• CAA Records: Present
• DNSBL Listed: 1 of 8 lists
• Operator Score: 0.2174 (Minimal)

## Threat Indicators

• Known Attacker: No
• Spam Source: No
• Tor Exit Node: No
• Blacklist Count: 0
• Known Campaigns: None identified
• Reputation Sources: None

## Neighborhood Analysis

The /24 subnet (51.161.65.0/24) shows elevated abuse characteristics:

• Abuse Density: 0.6094 (high)
• Total Siblings: 256
• Active Siblings: 207
• Threat Siblings: 156
• Inherited Risk Score: 24
• Risk Distribution: 0 high, 99 medium, 1 low

The subnet exhibits a 60.94% abuse rate, suggesting this IP shares infrastructure with known malicious actors.

## Observation History

Historical signals from June 2026 indicate:

• Consistent provider attribution to OVH hosting infrastructure
• Operator score maintained at "Minimal" (0.2174)
• Control plane signals present with DNSSEC validation
• No ownership changes observed
• Single threat observation recorded
• Not classified as persistently malicious

## Relationship Graph

47 relationships identified, all mapping to the same network identifier (OVH-CUST-281059690). No external entity relationships (hostnames, organizations, certificates) detected beyond network-level associations.

## Recommended Actions

Based on risk assessment and neighborhood context, the following firewall rules are recommended:

Immediate Mitigation

• iptables: `iptables -A INPUT -s 51.161.65.42 -j DROP`
• nftables: `nft add rule inet filter input ip saddr 51.161.65.42 drop`
• nginx: `deny 51.161.65.42;`
• pfSense: Block 51.161.65.42/32
• Cloudflare WAF: Block with expression `ip.src eq 51.161.65.42`
• AWS WAF: Add to block list with CIDR `51.161.65.42/32`

## Risk Assessment

Classification: Moderate Risk (Score: 40)

The IP demonstrates low individual threat indicators but operates within a high-abuse density subnet. The absence of open services reduces immediate exploitation risk, however the subnet-level abuse context warrants defensive blocking. The infrastructure association with Ahrefs.net suggests potential legitimate use, but the elevated neighborhood risk and lack of observable services indicate the IP may be part of a compromised or repurposed hosting environment.

Recommendation: Block at perimeter defense layers while monitoring for legitimate traffic patterns.

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