Autonomous System Numbers (ASNs) are essential for managing the flow of data across the global internet infrastructure. With IP addresses and connected devices proliferating rapidly, effectively leveraging ASNs is more critical than ever.
This beginner‘s guide will explain what ASNs are and why they matter. We‘ll also explore the top ASN online lookup tools, scripts, and APIs available today. Equipped with the knowledge of how to utilize these ASN resources efficiently, you‘ll be well on your way to enhancing your networking capabilities.
What is an ASN and Why Does it Matter?
An ASN or Autonomous System Number is a unique identifier assigned to groups of IP networks that have their own routing policies, known as Autonomous Systems (AS). ASNs are essential to enabling these independent networks to exchange routing information across the internet.
There are two types of ASNs:
- Public ASNs: Required for exchanging routes over the public internet
- Private ASNs: Only communicate with a single ISP using BGP routing
As seen in the chart above, global ASNs have grown rapidly over the past decade. As of 2022 there are over 97,000 ASNs in use according to CIDR Report. This growth mirrors the expanding number of organizations connecting resources across private and public networks.
Managing this scale of ASN routing data brings escalating challenges. That‘s why having the right ASN administration tools is so crucial. By obtaining your own ASN, you can benefit in the following ways:
- Increased network flexibility and portability
- Ability to directly peer with Internet Exchange Points
- Improved traffic control and network identity
- Set up external and internal BGP routing
As you can see, ASNs serve a vital purpose in how traffic flows around the global internet. That‘s why ASN lookup tools are so indispensable for any networking or cybersecurity professional.
Next, let‘s explore some of the top ASN lookup and database options available today…
7 Best ASN Lookup Tools and Databases
There is a wide range of ASN lookup tools available covering various use cases. Here we highlight some of the top options:
1. UltraDNS
UltraDNS offers one of the most user-friendly web-based ASN lookup options. Simply enter an AS number, company name, or IP address. UltraDNS will instantly return full details on the associated AS, including:
- IP owner
- Issuing registrar
- Registration dates
- Total IP ranges
- Live traffic stats
- And more…
With clean presentation of data and flexible search options, UltraDNS is a top choice for quick online ASN analysis.
2. APNIC Whois
As the Regional Internet Registry (RIR) for the Asia Pacific region, APNIC maintains the definitive whois database of organizations and their associated ASNs/IP resources for this part of the world.
The APNIC Whois lookup lets you input an IP or ASN to see crucial details like:
- When and where resources were allocated
- Network contacts
- Assignment history
- And more…
For Asia Pacific networking, APNIC Whois is an authoritative ASN lookup source.
3. ASNLookup
True to its name, ASNLookup offers a simple way to uncover the ASN and IP ranges tied to a company or organization. Just enter a name and it will fetch the ASN details.
ASNLookup also provides a free JSON API for integrating ASN data into applications. It‘s a programmable ASN checking option for developers.
As you can see, the output contains the essential ASN details needed for most use cases.
4. MX Toolbox
The MX Toolbox ASN lookup tool accepts either full or partial AS names/numbers as input. It will display possible matches based on your query. You can look up by IP, hostname, domain, or simply enter a URL to be redirected to relevant tools/data.
Useful for quick manual checking or automatable API access, MX Toolbox is versatile for many ASN lookup needs.
5. Hacker Target
As the name suggests, the Hacker Target ASN lookup site is geared toward cybersecurity analysts and penetration testers. Just plug in an ASN or IP address to reveal associated netblocks and org names.
Keep in mind – locations can be misleading here. An AS/IP showing for one country does not guarantee physical systems reside there. But for high-level ASN-to-IP mapping, Hacker Target delivers.
6. IPtoASN
Backed by technologies like Rust and OpenBSD, IPtoASN offers a speedy API for ASN lookups by IP address. It returns JSON outputs containing details like ISPs, netblocks, and country codes.
By identifying visitor IP details via ASN, you can better optimize site experiences. IPtoASN is purpose-built for that use case.
7. IPINFO
For those wanting an ASN lookup API without dealing with command line tools, IPInfo is a user-friendly option. Their ASN API accepts IP/ASN queries and returns JSON formatted outputs.
Useful data provided includes:
- AS owners
- Netblocks
- ISP names
- IP geolocation
- And more…
With batch lookup support and daily network dataset updates, IPInfo is an ASN API suitable for many needs.
Bonus Tools:
BGP Looking Glass
Offering views into BGP routing paths across networks, BGP Looking Glass services provide a unique vantage point for inspecting ASN connectivity. While not a lookup tool per se, it enables tracing the sequence of AS hops traffic takes. Useful for troubleshooting asymmetric or suboptimal routes.
MongoDB Atlas Peering Service
For users of MongoDB‘s Atlas cloud database, taking advantage of their integrated AS peering can improve performance and availability. With Atlas‘s global infrastructure footprint, optimized connectivity between your network and theirs is vital. Their interconnection service can assess the best approaches.
ASN BGP Lookup
This specialty lookup tool searches over 24,000 network prefixes and provides useful statistics on the surrounding address space coverage of a given ASN input. For researchers and analysts, these aggregate insights enable macro-level perspectives.
Evaluating ASN Lookup Needs
With dozens of ASN tools out there, how do you choose? First, carefully evaluate your use cases and data requirements.
Key criteria include:
- Output format: API, web interface, command line etc.
- Search inputs supported: ASN, IP address, company name
- Data returned: Ownership, netblocks, BGP paths, etc
- Geographic coverage: Global, regional focus
- Accuracy & completeness: Frequency of updates, reliability of datasets
Certain tools are optimized for developers, while others cater more to network admins or security analysts. Figuring out primary objectives and stakeholders will guide best fit.
Network Planning & Operations
If managing internal systems, priority may be on owning ASN records, viewing BGP routes, and integration with network DevOps automation. Regional registries like APNIC are handy here.
Application Development & Hosting
For cloud hosted or customer-facing services uptime and performance are critical. CDNs and optimized traffic routing relying on AS awareness are key.
Cybersecurity & Threat Detection
Linking suspect IPs back to source ASNs and watching BGP anomalies can uncover attacks. Tools focused on these security use cases help.
Emerging ASN Innovations & Challenges
While indispensable, legacy ASN and BGP systems strains are starting to show at global scale:
- IPv4 scarcity hinders growth
- Security and DDoS vulnerabilities
- Route leaks and errors
- Opaque data flows
Thankfully, promising technologies are emerging to modernize ASN data flows:
AS Path & Route Optimization – AI/ML powered analytics spot inefficient paths allowing smarter data routing and cost savings.
Predictive ASN Planning – By anticipating where new address demand will occur, proactive registry assignments optimize infrastructure.
Encrypted Transport – Techniques like BGPSec introduce authentication and encryption to ASN traffic, closing security gaps.
Expanded Address Space – Widespread IPv6 adoption alleviates scarcity pressures through exponentially bigger pools.
Realizing these improvements comes with cost/compatibility tradeoffs however. Transitioning global internet architecture changes slowly by nature. But further maturing these ASN/BGP enhancements remains vital work.
Conclusion
ASNs are the crucial glue that holds together routing across the patchwork of systems that make up the internet. By letting autonomous networks communicate, ASNs facilitate the rich interconnected experience we depend on.
Looking up and analyzing ASN data provides insights into security, traffic flows, and networking behavior that can profoundly impact system management.
We‘ve just covered the tip of the iceberg in terms of available ASN lookup tools. I encourage you to assess your needs, test drive the leading options, and incorporate ASN best practices appropriate for your systems.
The deeper you dig into the world of ASNs, the greater your ability to untangle and optimize internet infrastructure grows. These ASN lookup resources will launch you smoothly on that journey with data right at your fingertips.
