AS9999 ATTOKYO AT TOKYO Corporation

AS9999 (ATTOKYO) is held by AT TOKYO Corporation, a Japanese data-centre and colocation operator headquartered in Toyosu, Koto-ku, Tokyo. It is a facilities business first and a network operator second: the ASN exists to give colocation tenants routed address space and interconnection out of AT TOKYO's own halls, not to sell transit or serve consumers.

What it's used for

The routing footprint is small and stable rather than sprawling: 10 IPv4 prefixes carrying 20,224 addresses, plus a single IPv6 /32 (2405:1800::/32), announced with only 2 observed BGP neighbours. That combination is the signature of a customer-facing colocation network rather than a carrier. A wholesale or transit AS of any size peers with hundreds of others; an eyeball ISP holding twenty thousand addresses would still have a broad upstream mix. Two neighbours and a compact block list instead describe an AS whose job is to originate a handful of allocations on behalf of the businesses racked inside its facilities. The sampled reverse DNS points the same way: the PTRs that resolve belong to corporate customers rather than to residential subscribers or to AT TOKYO itself. The prefixes are AT TOKYO's own APNIC allocations, registered under the ATTOKYO netname and marked ALLOCATED PORTABLE, so this is not resold or brokered space.

Notable

• AT TOKYO operates carrier-neutral data centres in Japan, with its largest campus in the Tokyo bay-front area; the facilities, not the ASN, are the product.
• The ASN is sometimes tagged as a Cable/DSL/ISP network in third-party directories. The inventory does not support that reading: there is no eyeball-style reverse DNS and no broad peering fan-out.
• Address space is drawn entirely from APNIC and registered to the company itself, which rules out the multi-RIR, third-party-registrant pattern typical of IP leasing.