171.243.150.251📋 Copy

# Intelligence Briefing: 171.243.150.251/32

Classification: Moderate Risk — Residential ISP Address

Date: July 29, 2026

Analyst: IPDebrief Intelligence Unit

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## Executive Summary

IP 171.243.150.251 is a dynamic residential address assigned to Viettel's Vietnamese ISP network (ASN 7552, IRT-VNNIC-AP). The IP carries a moderate risk score of 40/100 with no active threat indicators. The address is associated with a residential broadband subscription (dynamic-adsl.viettel.vn) and shows no open services or ports.

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## Technical Profile

Network Attribution:

• Organization: Viettel Corporation (IRT-VNNIC-AP)
• ASN: 7552
• CIDR Block: 171.224.0.0/11
• Geolocation: Vietnam (Da Nang region)
• RIR: APNIC
• Registration: Vietnam National Internet Center (VNNIC)

DNS Resolution:

• PTR Record: dynamic-adsl.viettel.vn
• Forward Resolution: dynamic-adsl.viettel.vn (single hostname)
• Email Authentication: SPF and DMARC records present
• Service Status: No open ports; services: Firewalled / No Services

Threat Indicators:

• Risk Score: 40 (Moderate)
• Abuse Confidence Score: Not elevated
• Blacklist Count: 0
• DNSBL Listings: 2 of 8 lists
• Known Campaigns: None
• Tor Exit Node: No
• Spam Source: No
• Known Attacker: No

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## Neighborhood Analysis

Subnet: 171.243.150.0/24

Abuse Density: 16.67% (0.1667)

Classification: Mostly Clean

Sibling Distribution: 24 total IPs, 16 active

Risk Distribution in /24:

• High Risk: 1 IP
• Medium Risk: 6 IPs
• Low Risk: 16 IPs

Notable High-Risk Neighbor: 171.243.150.146 (Risk Score: 80)

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## Historical Observations

Observation Count: 100 signals recorded

Temporal Activity: Recent observations dated July 29, 2026

Historical Changes Detected:

• Ownership stability: No ownership changes observed
• Geolocation data: Multiple geolocation sources confirmed Vietnam origin
• Subnet classification: Consistently classified as mostly_clean
• Threat persistence: 0 threat observation count

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## Relationship Graph

Connected Entities:

• Network Association: VIETTEL-VN (2 relationships)
• DNS Associations: dynamic-adsl.viettel.vn (2 relationships)

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## Recommended Actions

Firewall/Filtering:

• Status: No specific blocking recommended
• Rationale: IP carries moderate risk with no active threat indicators; classified as residential ISP address

Monitoring:

• Monitor for any service openings or port scans
• Track DNSBL listing changes
• Observe subnet-level activity for correlated threats

Threat Hunting Considerations:

• The subnet contains one high-risk IP (171.243.150.146) that may warrant investigation
• Monitor for lateral movement or command-and-control activity from the Viettel network
• Residential IPs in this range may be associated with compromised customer devices

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## Conclusion

IP 171.243.150.251 represents a legitimate residential Vietnamese ISP address with moderate baseline risk. No immediate threat indicators or actionable intelligence suggest this IP requires blocking. Standard monitoring and contextual threat hunting are appropriate. The subnet's 16.67% abuse density warrants awareness but does not elevate this specific IP to high-risk status.

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