AS64515

Private AS Number, part of the range 64512 to 65534

Private Autonomous System Numbers (ASNs) are a subset of AS numbers reserved for internal or private use within networks that do not require global routing on the public Internet. Assigned by the Internet Assigned Numbers Authority (IANA), private ASNs are intended for use in scenarios where an organization operates a network that interacts with one or more external networks but does not directly connect to the global Border Gateway Protocol (BGP) routing table. These numbers, specified in RFC 6996, include the range 64512–65534 (16-bit ASNs) and 4200000000–4294967294 (32-bit ASNs).

Private ASN ranges
64512	65534
4200000000	4294967294

Private ASNs are most commonly used in environments like corporate intranets, private cloud setups, and for connecting autonomous systems via BGP in cases where public ASNs are not necessary. For instance, they are essential in scenarios involving multi-homed network setups using BGP where the network does not advertise routes to the global Internet but needs to differentiate internal routing policies. If a private ASN is inadvertently advertised to the public Internet, transit providers typically strip it and replace it with their public ASN.

Vultr, a cloud provider, uses private ASNs to establish BGP sessions with their VPS customers:


Vultr Internal AS: 64515
Vultr IPv4 BGP Neighbor: 169.254.169.254
Vultr IPv6 BGP Neighbor: 2001:19f0:ffff::1
BGP Multihop setting: 2

Proper usage of private ASNs ensures better network isolation and prevents conflicts with globally unique ASNs. For anyone exploring a looking glass system for private ASNs, it’s crucial to understand that while these numbers won’t appear in global route tables, they might exist on the specific provider's network. For example, one of BGP.RUN's peer uses private AS numbers for peering, which results in the following paths (reversed) for the prefix:

			
Prefix:
45.131.253.0/24

Paths:
AS13030 AS34927
AS13030 AS1836 AS58057
AS13030 AS1299 AS56655 AS53356
AS13030 AS1299 AS35847 AS399646
AS13030 AS396998 AS52025 AS47272 AS212895
AS13030 AS1299 AS47272 AS212895
AS13030 AS1299 AS20473 AS65534 AS64515
AS13030 AS6939 AS61218 AS58057
AS13030 AS1299 AS33554 AS53356
AS13030 AS1299 AS906 AS52025 AS212895
AS13030 AS15830 AS203446 AS212895

To avoid confusion we are filtering out the private AS numbers in the reported paths.