BGP peering is direct traffic exchange between two networks. Better peering means shorter paths and lower latency for users.

BGP ASN Lookup

Look up BGP Autonomous System Numbers (ASNs) for major networks, cloud providers, CDNs, and ISPs. Search by company name or ASN to find network details, peering information, and routing context — essential for network engineers, peering coordinators, and troubleshooting routing issues.

Search by ASN or Organization Name

ASN	Organization	Type	Country	Notable Prefixes

What Is a BGP Autonomous System Number?

An Autonomous System Number (ASN) is a unique identifier assigned to a network (or group of networks) that operates under a single routing policy. ASNs are used by the Border Gateway Protocol (BGP) — the routing protocol that connects all networks on the internet. When you browse a website, BGP routes your traffic through a chain of autonomous systems to reach the destination.

ASNs are assigned by Regional Internet Registries (RIRs) like ARIN, RIPE, and APNIC. Understanding ASNs helps with peering decisions, routing troubleshooting, and network security analysis. Check your own connection details with our What Is My IP tool.

ASN Types and Ranges

Type	Range	Format	Usage
16-bit Public	1 – 64,511	AS####	Original public ASNs
16-bit Private	64,512 – 65,534	AS####	Internal/private use
32-bit Public	131,072 – 4,199,999,999	AS######	Extended public ASNs (RFC 6793)
32-bit Private	4,200,000,000 – 4,294,967,294	AS######	Extended private use
Reserved	0, 65535	—	Protocol reserved

How BGP Routing Works

BGP is the glue that holds the internet together. Here's a simplified view of how your traffic finds its way:

Your ISP (e.g., AS7922 Comcast) announces your network via BGP to its peers.
Each peer propagates the route to its own peers, creating a chain of AS paths.
When you access Google (AS15169), BGP determines the shortest AS path from your ISP to Google.
Traffic flows through the chain of autonomous systems along the selected path.

The quality of your ISP's peering directly affects latency and speed. Use our Network Latency Test and Speed Test to measure the impact. If latency to specific services is high, your ISP may have poor peering with that network. Check with our Cloud Region Latency Checker.

Pro Tip: You can trace the AS path to any destination using traceroute and looking up each hop's ASN. Tools like Hurricane Electric BGP Toolkit provide detailed AS path information. If you notice traffic taking an unusually long path (many AS hops), your ISP may have limited peering — consider an ISP with better connectivity.

Tier 1, Tier 2, and Tier 3 Networks

Tier	Description	Examples	Peering
Tier 1	Global backbone, no transit purchases	Lumen (AS3356), Cogent (AS174), NTT (AS2914)	Settlement-free with all Tier 1s
Tier 2	Regional/national, buys some transit	Comcast (AS7922), Charter (AS20001)	Peers with some Tier 1s, buys transit from others
Tier 3	Local ISP, buys all transit	Small regional ISPs	Purchases transit from Tier 1/2

Note: This tool uses an embedded database of well-known ASNs for instant offline lookup. For real-time, comprehensive ASN data including all 100,000+ registered ASNs, use the WHOIS protocol or online services like Hurricane Electric's BGP Toolkit. Our database covers major cloud providers, CDNs, social platforms, and large ISPs.

BGP and Your Internet Performance

BGP routing decisions directly impact your network performance. Factors include:

AS path length — Fewer AS hops generally means lower latency. Test with our Ping Test.
Peering quality — Direct peering between your ISP and a content provider is faster than going through transit.
DNS routing — CDN DNS (like Cloudflare's 1.1.1.1) routes you to the nearest edge. Test with our DNS Lookup.
ISP throttling — Some ISPs throttle traffic to specific ASNs. Check with an ISP throttling test.
QoS policies — QoS can prioritize traffic to specific destinations on your local network.

If certain websites or services are slow while others are fast, the issue is likely BGP routing between your ISP and that service. Use our Network Latency Test to compare latency to different providers.

Looking Up Your ISP's ASN

# Using whois
whois -h whois.radb.net your-ip-address

# Using dig (DNS-based lookup)
dig +short TXT your-ip-reversed.origin.asn.cymru.com

# Example: Look up 8.8.8.8
dig +short TXT 8.8.8.8.origin.asn.cymru.com
# Returns: "15169 | 8.8.8.0/24 | US | arin | 1992-12-01"

Check your current IP and connection details with our What Is My IP tool. For understanding how your traffic is routed, monitor with network traffic monitoring.

Key Takeaways

ASNs uniquely identify networks on the internet; BGP uses them to route traffic between networks.
Tier 1 networks form the internet backbone; your ISP connects to them for global reachability.
Shorter AS paths generally mean lower latency — ISP peering quality matters.
Private ASNs (64512-65534) are for internal use and should never appear on the public internet.
BGP routing decisions directly affect your speeds to specific services.
Use our What Is My IP tool to identify your ISP and connection details.

Video: BGP and How the Internet Works

Related Tools & Guides

Frequently Asked Questions

What is an Autonomous System?

An Autonomous System (AS) is a collection of IP networks and routers under the control of a single organization that presents a common routing policy to the internet. Each AS is identified by a unique ASN. Your ISP, Google, Amazon, and Cloudflare each have their own ASNs.

How do I find my ISP's ASN?

Visit our What Is My IP tool to see your public IP, then look it up using whois or online tools. Your ISP's ASN is part of the WHOIS record for your IP address.

Why does BGP matter for my internet speed?

BGP determines the path your traffic takes across the internet. Poor BGP routing can send traffic through extra hops, increasing latency. If a specific site is slow, the AS path between your ISP and that site may be suboptimal. Compare with our Latency Test.

What happens during a BGP hijack?

A BGP hijack occurs when a network announces IP prefixes it doesn't own, redirecting traffic through unauthorized paths. This can cause outages, surveillance, or traffic interception. RPKI (Resource Public Key Infrastructure) helps prevent hijacks.

What is BGP peering?

BGP peering is the arrangement between two networks to directly exchange traffic. Settlement-free peering means neither side pays; transit means one network pays the other for connectivity. Better peering = shorter paths = lower latency for end users.

Can I influence BGP routing as an end user?

Not directly. BGP routing is controlled by ISPs and network operators. However, you can choose an ISP with better peering, use a VPN to alter your traffic path, or change your DNS to be routed to closer CDN edges.

About Tommy N.

Tommy is the founder of RouterHax and a network engineer with 10+ years of experience in home and enterprise networking. He specializes in router configuration, WiFi optimization, and network security. When not writing guides, he's testing the latest mesh WiFi systems and helping readers troubleshoot their home networks.