What is ASN (Autonomous System Number)?

ASN stands for Autonomous System Number. It is a unique number assigned to each autonomous system (AS) on the internet, which represents a group of connected networks that share a common routing policy.

An autonomous system is a collection of interconnected networks that are under the same administrative control and use a common routing strategy. This can include a single organization's network, or a group of networks that have been peered with each other. Each AS has its own AS number, which is used to identify it in BGP (Border Gateway Protocol) messages and other routing protocols.

The ASN is used to identify the origin of IP packets as they travel across the internet, allowing routers to determine where to forward the packets based on the routing policies of the AS. The ASN is also used to help prevent route hijacking and other types of network attacks.

In summary, ASN is a unique identifier for an autonomous system, which represents a group of connected networks that share a common routing policy, and it is used to identify the origin of IP packets as they travel across the internet.