The Ultimate Guide to ASN Lookup Tools for Your Business

As someone passionate about technology, the interconnected nature of networks has always fascinated me. Autonomous System Numbers (ASNs) play a key role in gluing the internet together securely. However, their significance often goes under the radar among businesses.

In my career as a network analyst, I’ve seen firsthand the many ways ASN data can provide invaluable visibility for organizations. Looking up and leveraging ASN intelligence has helped troubleshoot subtle connectivity issues, identify potential security threats, and optimize network architecture for numerous clients.

That’s why I’ve curated this comprehensive guide on the top ASN online lookup tools and APIs available today. Whether you’re a fellow network geek, IT leader or business owner, my goal is to help you unlock the full potential of ASN lookup tools to take your infrastructure and security capabilities to the next level.

Let’s get started!

Demystifying ASNs

Before diving into the tools, it’s important to understand what exactly ASNs are and why they matter.

An Autonomous System (AS) is a group of IP networks and routing policies that are under the control of one entity. Each AS is assigned a unique ASN, which allows it to exchange routing information with other ASes using the Border Gateway Protocol (BGP).

Here are some key stats on the global AS network:

There are over 96,000 ASNs in use as of 2022 (Source)
Just 100 ASes handle over 50% of global traffic. (Source)
ASNs like AS15169 (Google) and AS32934 (Facebook) handle enormous amounts of traffic.

This illustrates the consolidation of control among a handful of ASes. Understanding AS landscape is vital for companies transmitting data worldwide.

Why Should Businesses Care About ASNs?

ASNs act like passports, enabling networks to share routing data securely. Looking them up provides numerous benefits:

Gain Visibility

See relationship between IPs – Identify owners and interconnections. Critical for security and planning.
Detect anomalies – Spot misconfigured/hijacked IP spaces. Helps avoid outages.
Monitor peer traffic – Monitor traffic exchanged with network partners. Can reveal attacks or misuse.

Troubleshooting

Diagnose problems faster – ASN context aids identifying source of issues. Reduces MTTR.
Optimize connectivity – Determine best interconnection points to improve performance.

Compliance and Control

Data residency – Ensure customer data stays within approved geographies.
Fraud prevention – Detect unauthorized/fake IP spaces. Stops abuse.
Filtering – Selectively block malicious IPs based on ASN intelligence.

Market Intelligence

Competitor monitoring – Analyze adoption and traffic metrics for rival ASes.
Partnership opportunities – Identify potential network partners and peering options.

Clearly, ASNs contain a wealth of actionable insights for security, engineering and business teams. Now let’s explore tools to harness this data.

Top ASN Lookup Tools and APIs

There are diverse options available for looking up ASN data, each with unique strengths:

Tool	Description	Use Cases
UltraDNS	User-friendly web interface for quick lookups.	Ad hoc manual queries, basic checks.
APNIC	RIR database for Asia Pacific IPs.	Authoritative APAC data.
BGPView	Advanced web portal for ASN analytics.	Troubleshooting connectivity and routing issues.
IPWHOIS	Python package for ASN lookups via CLI/scripts.	Automation, integrate into apps and workflows.
Hurricane Electric	Simple JSON API for ASN data.	Clean machine readable ASN data feed.
IP2Location	Full featured ASN lookup API.	Flexible lookups via SDKs, bulk analysis, caching.
RIPEstat	Access raw RIR database for European IPs.	Get authoritative data unavailable elsewhere.

Let‘s explore the leading tools in each category in more depth.

UltraDNS – Convenient Web Lookup

UltraDNS offers a user-friendly web interface for quick ASN lookups. Just enter an IP address, ASN or organization – it will display details like AS owner, associated IPs, location and more.

It‘s perfect for ad hoc manual queries when you just need a quick check on a specific IP. However, researchers may find it limiting since bulk lookups require an enterprise account. Also, the data is not always fully up to date compared to RIR sources.

Overall, UltraDNS is great for basic lookups due to its simplicity. But power users may want access to authoritative datasets.

APNIC – Authoritative Asia Pacific ASN Data

For companies operating in Asia Pacific, APNIC is the go-to source for authoritative ASN data. APNIC maintains the WHOIS database delegated to it by IANA, so their data for the region is always accurate.

The free online tool allows querying ASNs by IP address or organization name. The interface is a bit dated but the data quality is excellent. Other RIRs like ARIN, RIPE etc provide similar access for their respective regions.

In my experience, APNIC lookups are invaluable for clients with APAC presence who need 100% reliable data. The main limitation is lack of flexibility – custom reporting or bulk analysis is not possible.

BGPView – Advanced Troubleshooting and Analytics

If you need to go beyond basic lookups, BGPView provides an advanced web portal for interactive ASN analytics. You can analyze details like AS paths, geoip info, DNS records and traffic volumes associated with an AS.

It‘s one of my favorite tools for troubleshooting obscure routing and connectivity issues quickly. Seeing the AS path and interconnections provides much needed context.

BGPView isn‘t cheap at $29/mo minimum but it‘s worth it for the power and flexibility. The only downside is data is not completely authoritative since it relies on multiple sources.

IPWHOIS – Integrate ASN Lookups into Workflows

For automation and integration needs, IPWHOIS is my top choice. It‘s a Python package that allows ASN lookups directly from the command line or scripts. Just pass an IP and you get structured ASN data back.

This makes IPWHOIS great for building ASN capabilities right into your applications and workflows. We utilize it heavily in monitoring and analytics systems for clients to enrich network intelligence.

Being Python, IPWHOIS can pose some dependencies and performance challenges for large scale usage. Overall though, it‘s invaluable for developers and network engineers alike.

Hurricane Electric – Machine Consumable ASN API

If you need an ASN lookup API, Hurricane Electric offers a simple and elegant solution. Their JSON API allows programmatic ASN queries with a clean response structure:

GET https://api.he.net/asn/8.8.8.8 

{
  "as": "AS15169",  
  "prefix": "8.8.8.0/24",
  "country": "US",
  // etc...
}

This streamlined JSON output makes ASN data easy to consume across applications written in any language. Rate limiting is generous for most use cases.

For full featured API capabilities though, IP2Location may be preferable. But if a lightweight ASN lookup API is all you need, Hurricane Electric hits the sweet spot.

IP2Location – Feature Rich ASN API

On the other end of the spectrum, IP2Location provides a full API toolkit for advanced ASN lookups. You get options for bulk analysis, caching, multiple response formats, libraries for easy integration and more.

We utilize their API in fraud detection applications to identify suspicious/hijacked IP ranges in real-time. The bulk lookup capability and downloadable databases are invaluable for this purpose.

Downsides are the learning curve and pricing model. Documentation is thorough but IP2Location has many advanced options. And you need an API key – though they do offer an affordable free trial.

RIPEstat – Access Raw RIR Data

Lastly, for European IPs, RIPEstat provides authoritative ASN data straight from the source. As one of the 5 Regional Internet Registries, RIPE maintains the canonical ASN/IP assignment records for its region.

RIPEstat allows web access to this raw ASN data. The interface takes some learning but unlocks details not available elsewhere. It‘s also completely free to use with no limits.

In summary, RIPEstat is a must for network engineers needing 100% accurate and exhaustive European ASN data. But the learning curve may deter more casual users.

Apply ASN Intelligence to Your Business

I hope this guide has revealed just how much valuable intelligence ASN lookups can provide for security, engineering and executive teams.

To recap, unlocking ASN data can help your organization:

Monitor security threats and stop abuse
Optimize network architecture and performance
Diagnose outages and connectivity issues faster
Maintain compliance with regulations
Gain competitive intelligence

The possibilities are endless! I highly recommend evaluating tools like UltraDNS for easy lookups and BGPView for advanced analytics. Integrating ASN lookups into your workflows via IPWHOIS and IP2Location can work wonders.

Feel free to reach out if you need any help applying ASN intelligence to strengthen your infrastructure and enable business success! I‘m always happy to chat networks.