ASN WHOIS Lookup
Look up detailed information about Autonomous System Numbers (ASN) including organization details, registry information, IP prefixes, country allocation, and network infrastructure. Supports both AS number and organization name searches.
ASN Lookup
Sample ASNs:
About ASN WHOIS Lookup
An Autonomous System Number (ASN) is a unique identifier assigned to an autonomous system - a collection of IP networks and routers under the control of a single organization. ASN lookups provide valuable information about network ownership, IP address allocations, routing policies, and contact information for network administrators. This tool queries authoritative Regional Internet Registry (RIR) databases including ARIN, RIPE NCC, APNIC, LACNIC, and AFRINIC to provide comprehensive ASN information.
About ASN WHOIS Lookup
A comprehensive ASN (Autonomous System Number) WHOIS lookup tool that provides detailed information about network infrastructure including organization ownership, registry allocation (ARIN, RIPE, APNIC, LACNIC, AFRINIC), IP address ranges (IPv4 and IPv6 prefixes), country assignment, allocation dates, and contact information. Essential for network analysis, security research, and internet infrastructure investigation.
Why use a ASN WHOIS Lookup?
Understanding ASN details is critical for network security analysis, BGP routing investigations, IP allocation research, and cybersecurity threat intelligence. This tool eliminates the need for multiple command-line WHOIS queries by providing comprehensive ASN information in a user-friendly interface, helping you analyze network ownership, identify infrastructure relationships, and conduct security assessments efficiently.
Who is it for?
Essential for network engineers managing BGP routing and peering relationships, cybersecurity professionals investigating threats and analyzing attack sources, security researchers conducting internet infrastructure studies, system administrators troubleshooting connectivity issues, and compliance officers tracking data center locations and network ownership for regulatory requirements.
How to use the tool
Enter an ASN (e.g., AS15169 or 15169) or organization name in the search field
Click 'Lookup' to retrieve comprehensive ASN information from WHOIS databases
Review organization details including name, registry, and country allocation
Analyze allocated IP prefixes (both IPv4 and IPv6 address ranges)
View contact information and administrative details when available
Export results for documentation, compliance reporting, or security analysis
Key Features
Multi-Registry Support
Query across all major Regional Internet Registries (RIRs) including ARIN, RIPE NCC, APNIC, LACNIC, and AFRINIC for comprehensive global coverage
IP Prefix Analysis
View all IPv4 and IPv6 prefixes allocated to the ASN with expandable tables showing CIDR blocks and allocation details
Organization Search
Search by organization name to find related ASNs and network infrastructure owned by the same entity
Related ASN Discovery
Identify other ASNs owned by the same organization to map complete network infrastructure
Export Functionality
Export lookup results in JSON or CSV format for further analysis, reporting, or integration with other security tools
Recent Lookups History
Track recently searched ASNs for quick reference and comparison across multiple network investigations
Common Use Cases
Security Threat Analysis
Scenario: A security analyst receives abuse reports from IP addresses and needs to identify the responsible organization and contact information
✓ Quickly lookup ASN ownership details, contact information, and all related IP prefixes to properly report abuse and assess threat scope
BGP Routing Investigation
Scenario: A network engineer notices routing anomalies and needs to verify ASN ownership and peering relationships
✓ Instantly access ASN details, registry information, and IP prefix allocations to validate routing configurations and identify potential hijacking attempts
Compliance and Geolocation
Scenario: A compliance officer needs to verify data center locations and network ownership for GDPR or data sovereignty requirements
✓ Look up ASN country allocation, organization details, and registry information to ensure infrastructure compliance with regulatory requirements
Peering Partner Research
Scenario: A network administrator is evaluating potential peering partners and needs detailed information about their network infrastructure
✓ Research ASN details, allocated IP space, and organization information to make informed decisions about peering arrangements
Why Choose This Tool
- User-friendly web interface eliminates need for command-line WHOIS tools
- Queries multiple RIRs automatically for comprehensive global coverage
- Expandable IP prefix tables with detailed CIDR block information
- Organization name search to discover related network infrastructure
- Export functionality for integration with security and compliance workflows
- Recent lookups history for efficient multi-ASN investigations
- Mobile-responsive design for network investigation on the go
1M+ ASN lookups performed
Queries authoritative RIR WHOIS databases
No query logging or data retention
99.9% service availability
Frequently Asked Questions
What is an ASN (Autonomous System Number)?
An ASN is a unique identifier assigned to an autonomous system (AS) - a collection of IP networks and routers under the control of a single organization that presents a common routing policy to the Internet. ASNs are essential for BGP routing between networks.
How do I find an ASN for an IP address?
Use our IP Address Lookup tool to find the ASN associated with any IP address, then use this ASN WHOIS Lookup tool to get detailed information about that network.
What are Regional Internet Registries (RIRs)?
RIRs are organizations responsible for allocating and managing IP addresses and ASNs in specific geographic regions: ARIN (North America), RIPE NCC (Europe/Middle East), APNIC (Asia-Pacific), LACNIC (Latin America), and AFRINIC (Africa).
Why do some ASNs have multiple IP prefixes?
Organizations often receive multiple IP address allocations over time, acquire networks through mergers, or operate in different geographic regions. Each allocation appears as a separate prefix in the ASN's routing table.
Is this information updated in real-time?
The tool queries authoritative WHOIS databases which are typically updated within 24-48 hours of any changes. Some information may be cached briefly for performance.
Can I use this for abuse reporting?
Yes, the contact information provided includes abuse contacts and administrative contacts that can be used to report network abuse, security issues, or policy violations.
Technical Specifications
Supported Formats
- ✓All 16-bit ASNs (0-65535)
- ✓All 32-bit ASNs (65536-4294967295)
- ✓ARIN (North America)
- ✓RIPE NCC (Europe, Middle East)
- ✓APNIC (Asia-Pacific)
- ✓LACNIC (Latin America)
- ✓AFRINIC (Africa)
- ✓IPv4 prefix lookups
- ✓IPv6 prefix lookups
- ✓Organization name searches
- ✓JSON and CSV export formats
Limits & Performance
- •Validations: Real-time WHOIS database queries
- •Response Time: Typically 1-3 seconds
- •Browsers: All modern browsers with JavaScript enabled
Pro Tips
- You can enter ASN with or without the 'AS' prefix (e.g., 'AS15169' or '15169')
- Use organization name search to discover all ASNs associated with a company
- IP prefix lists can be expanded to see complete CIDR block allocations
- Export results before conducting multiple lookups to maintain a research record
- Recent lookups history helps compare related ASNs during investigation
- Check allocation dates to understand when an ASN was assigned
- Review all IP prefixes to understand the complete network footprint
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