AS9600 SONYTELECOM So-net Corporation

AS9600 (SONYTELECOM) is registered to So-net Corporation, the Sony group's ISP business (now Sony Network Communications). The reverse DNS shows what the AS actually carries: every sampled address resolves under cust.bit-drive.ne.jp. bit-drive is the Sony group's corporate network and cloud service brand, not the consumer So-net product.

What it's used for

This is a business-access network. It announces 15 IPv4 prefixes totalling 82,944 addresses, mostly /19s and /20s scattered across many unrelated parent blocks (219.106.224.0/19, 211.9.32.0/19, 61.45.192.0/19, 210.172.0.0/19 and so on), plus a single IPv6 /32, 2001:298::/32. That fragmented, many-small-blocks footprint is what a provider accumulates by assigning customer subnets over years, and the cust. label in the PTRs confirms the addresses are handed to customers rather than used for the operator's own servers. Only one observed BGP neighbour, on ~83k addresses, rules out any wholesale-transit role entirely: this AS sits behind its upstream and serves the businesses connected to it, over the fibre, VPN and managed-connectivity products bit-drive sells.

Notable

• Do not read this as Sony's consumer eyeball network. So-net's residential broadband and NURO subscribers live on a different AS. AS9600 is the corporate side.
• The bit-drive corporate cloud and network business was moved by corporate split to Sony Biz Networks Corporation, so the marketing brand and the registered AS holder no longer match exactly. The registry still says So-net.
• The mix of 61.x, 202.x, 203.x, 210.x, 211.x, 218.x, 219.x and a modern 103.22.152.0/22 reflects a long allocation history rather than one contiguous grant.