ASN Lookup

Autonomous System Number Purpose

An Autonomous System Number (ASN) is a unique identifier assigned to a network or group of networks that are under the control of a single organization and have a unified routing policy.

• • Identifies networks in BGP routing
• • Enables inter-domain routing decisions
• • Provides network ownership information
• • Facilitates peering agreements
• • Helps with network troubleshooting

ASN Types and Ranges

Key ASN Information Fields

BGP and ASN Relationship

Border Gateway Protocol (BGP) uses ASNs to make routing decisions and prevent loops.Each ASN represents a routing domain with its own policies.

• • ASNs identify the path a packet takes
• • Prevent routing loops through AS-PATH
• • Enable policy-based routing decisions
• • Support route aggregation and filtering

Route Announcement Process

Common BGP Attributes

Types of Network Relationships

Peering Policies

Internet Exchange Points (IXPs)

IXPs are physical locations where multiple networks connect to exchange traffic efficiently.

• • Reduce latency and improve performance
• • Lower transit costs through direct peering
• • Increase network resilience and redundancy
• • Enable local content delivery

Common ASN Issues

Diagnostic Tools

Best Practices

• • Maintain accurate routing registry entries
• • Implement proper route filtering
• • Monitor BGP announcements regularly
• • Use RPKI for route origin validation
• • Document peering policies clearly
• • Keep contact information up to date

When to Contact Support

• • Suspected route hijacking or leaks
• • Peering relationship issues
• • Incorrect ASN information in databases
• • BGP convergence problems
• • Network reachability issues