ASN Lookup Tool – Find Autonomous System Numbers Instantly

What Is This Tool?

The ASN lookup tool allows users to retrieve data about an Autonomous System Number (ASN), a unique identifier assigned to networks involved in BGP (Border Gateway Protocol) routing on the internet. By entering an ASN, domain, or IP address, the tool fetches:

• Network owner information
• Routing prefixes
• Related IP blocks
• Upstream and downstream peers
• Country and registry data

This tool is ideal for:

• Network administrators tracking IP ownership
• Cybersecurity teams investigating threats
• Developers troubleshooting BGP routing
• Researchers analyzing internet infrastructure

Whether you need a BGP AS number lookup, ASN search, or autonomous system number search, this tool delivers all the data you need.

Key Features & Benefits

• 🔍 Fast ASN Number Lookup - Instant results for ASN number lookup—no delays, no throttling.
• 🌐 Autonomous System Search by IP or Domain - Search by domain name, ASN, or IP address for flexible investigations.
• 🔒 No Login or Installation - This is a web-based ASN lookup tool. No account or software needed.
• 🆓 100% Free to Use - Use the full functionality with no cost, no hidden fees.
• 📡 Supports BGP AS Lookup - Access BGP AS number lookup and routing peer relationships with ease.
• 🧠 Accurate & Updated Data - Get real-time info pulled from public routing registries and databases.

Real-World Use Cases

• 🔧 Network Troubleshooting - System administrators rely on ASN lookup tools to determine why certain routes are dropping, identify upstream peers, and confirm IP ownership.
• 🕵️ Cybersecurity Investigations - Security teams use autonomous system number lookup to trace malicious IPs, identify suspicious routing changes, or detect phishing campaigns tied to specific networks.
• 📊 Academic & Infrastructure Research - Internet infrastructure researchers use ASN search to track the growth of ISPs, measure decentralization, and study BGP topology changes.
• 🛡️ VPN and Proxy Verification - Online platforms and services use ASN number lookup to detect if a user is connecting via known VPN providers or datacenters.
• 💼 IP Asset Management - Large enterprises with multiple IP allocations use ASN IP lookup to manage and audit their network resources effectively.

Why Choose This Tool?

• 🚀 Blazing fast ASN queries
• ✅ Accurate BGP data & prefix info
• 🔍 Multiple search input options (ASN, domain, IP)
• 🛠️ No setup or technical background required
• 🌍 Supports global ASNs and registries (ARIN, RIPE, APNIC, etc.)
• 🔄 Real-time and regularly updated data feeds
• 💸 Always free, with no usage caps

How It Works – ASN Lookup Explained

Follow these quick steps to find ASN information:

1. Enter an IP address, domain name, or ASN number in the search bar.
2. Click "Lookup" to start the query.
3. The tool queries multiple public routing databases and returns:
• ASN ownership details
• IP prefixes and blocks
• Registry and country
• Routing peers and more
4. Review and export results as needed.

Our tool ensures fast and thorough autonomous system number lookup for all major internet regions.

Pro Tips for Best Results

• Use full ASN numbers (e.g., AS15169) for precise results
• When searching by IP, ensure it's a public IPv4 or IPv6 address
• Try domain lookup if the ASN or IP is unknown
• Save results for later network audits
• Use regularly to monitor your infrastructure or detect changes

FAQs – ASN Lookup & BGP AS Search

Testimonials or Reviews

“This tool is a lifesaver for BGP troubleshooting. Super fast and reliable.”

“Great for identifying rogue networks during security audits.”

“I use it daily to check VPN exit nodes and datacenter ASNs. Love it.”

Disclaimer

Disclaimer: This tool uses publicly available BGP and routing data. While results are accurate and regularly updated, use for informational purposes only. Some edge cases may show outdated or partial data.