ISP & ASN Lookup - Your Internet Provider & Network Details

Find your Internet Service Provider (ISP) and Autonomous System Number (ASN) instantly. Learn how networks connect through peering and transit, why internet routing changes, and understand the infrastructure that powers your connection to the web.

What is an Autonomous System (AS)?

Definition

An Autonomous System is a network of IP prefixes under the control of one or more network operators that presents a common routing policy to the internet.

Think of it as:
  • • A neighborhood in the internet city
  • • Each has a unique ASN (like a postal code)
  • • Contains multiple IP address ranges
  • • Managed by a single organization

ASN Examples

AS15169
Google LLC
AS32934
Facebook/Meta
AS16509
Amazon.com, Inc.
AS7922
Comcast Cable
Fun fact: ASNs are 32-bit numbers, originally managed as 16-bit (1-65535). Today we have 4-byte ASNs to accommodate the growing internet. Your ISP's ASN identifies the network infrastructure you're connected to.

Peering & Transit 101

How Networks Connect

Peering

Free, direct connections between networks of similar size. Both networks benefit from shorter paths and reduced costs.

✅ No cost to exchange traffic
✅ Better performance
✅ Reduced latency

Transit

Paid service where a larger network (provider) carries traffic for a smaller network (customer) to reach the global internet.

💰 Customer pays provider
🌐 Access to full internet
📈 Scalable capacity

Internet Exchange Points (IXPs)

IXPs are physical locations where multiple networks connect to exchange traffic. They're like internet switchboards that keep traffic local and improve performance.

Major IXPs:
• DE-CIX Frankfurt (Germany)
• AMS-IX Amsterdam (Netherlands)
• LINX London (UK)
• Equinix Ashburn (US)

Benefits of IXPs

  • Reduced Latency: Shorter paths between networks
  • Lower Costs: Less reliance on expensive transit
  • Better Performance: Local traffic stays local
  • Redundancy: Multiple connection options

Why Latency Varies

Your ping times to different destinations depend on the path your packets take through the internet. Here's what affects your latency:

Physical Factors

  • Distance: Light travels ~200,000 km/s in fiber
  • Routing: Packets may take indirect paths
  • Congestion: Busy links cause queuing delays
  • Equipment: Routers add processing time

Business Factors

  • Peering: Direct connections are faster
  • Transit costs: Cheaper routes may be longer
  • Politics: Some networks don't peer with others
  • CDNs: Content closer to you is faster
Why routes change
BGP (Border Gateway Protocol) constantly updates routes based on network conditions, business relationships, and failures. A server in the same city might sometimes route through another continent due to these factors.

Understanding Your Network Path

Your Connection Hierarchy

1Your Device → Home Router
2Home Router → ISP Equipment
3ISP → Regional Network
4Regional → Internet Backbone
5Backbone → Destination Network

Network Tiers

Tier 1
Global networks that don't pay anyone for transit. Examples: Verizon, AT&T, NTT, Cogent
Tier 2
Regional networks that peer with some and pay others. Most ISPs and cloud providers fall here.
Tier 3
Local networks that primarily purchase transit. Your home ISP is likely Tier 3.

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