You found AS16509 behind an IP address and want to know what it is. AS16509 is one of Amazon's primary autonomous systems, the backbone of AWS. This page explains what the ASN covers, why AWS addresses are everywhere in logs, and how to treat them.
What is AS16509?
AS16509 is one of the main Autonomous System Numbers operated by Amazon, covering Amazon Web Services infrastructure. It announces a very large share of AWS IP space, so a route from AS16509 means the address sits in Amazon's cloud. For background, see what an ASN is.
- ASN: AS16509
- Operator: Amazon.com / Amazon Web Services
- Type: Hosting / cloud
- Note: Amazon announces from several ASNs, including AS14618; AWS also publishes its ranges as ip-ranges.json
What runs on AS16509?
Everything a customer can launch on AWS: EC2 servers, Lambda functions, containers, and the services built on them. Because AWS is the largest cloud provider, AS16509 is one of the most common hosting ASNs you will see. It carries a huge amount of legitimate production traffic and, because instances are easy to spin up, a large volume of bots and scrapers too.
Why you see AS16509 in your logs
AWS IPs appear constantly because so much of the internet runs on them, from monitoring services and legitimate API clients to automated abuse. Since AS16509 is a data-center network, its traffic is server-originated, so it should be scored differently from residential users.
Should you block AS16509?
No, not as a whole. Blocking AWS would cut off an enormous amount of legitimate business traffic, including partners and services your own product may depend on. Treat AS16509 as a hosting ASN, raise scrutiny on sensitive actions, and combine it with other signals rather than blanket-blocking.
How to check an IP against AS16509
To confirm an IP is AWS, look up its ASN. Abstract's free ASN Lookup tool returns the ASN, operator, and type for any address. In production, the IP Intelligence API returns the ASN plus is_hosting and related flags in one request, so AWS traffic can be flagged in real time at signup, checkout, or login. It is the data behind bot detection and ad fraud defenses.
Frequently Asked Questions
What is AS16509?
AS16509 is one of Amazon's primary Autonomous System Numbers, covering AWS infrastructure. It announces a large portion of Amazon's cloud IP ranges.
Why are AWS IPs in my logs?
A huge share of internet services run on AWS, so AS16509 traffic is everywhere, spanning legitimate applications, monitoring tools, and automated abuse launched from EC2 instances.
Does Amazon use only AS16509?
No. Amazon announces from several ASNs, including AS14618, and publishes its full IP ranges as a JSON file. AS16509 is the best-known but not the only one.
Should I block AS16509?
No. Blocking AWS would sever large amounts of legitimate traffic. Treat it as a higher-risk hosting ASN and score it with other signals.
How do I check if an IP is AWS?
Look the IP up in Abstract's ASN Lookup tool or via the IP Intelligence API to see whether its ASN is AS16509 or another Amazon ASN.
Get your free
IP Geolocation
key now
See why the best developers build on Abstract
get started for free
