AS9891 CSLOX-IDC-AS-AP CS LOXINFO Public Company Limited.

AS9891 (CSLOX-IDC-AS-AP) is held by CS LoxInfo Public Company Limited (CSL), a Bangkok-based ICT provider founded in 1994 and part of the AIS group since 2018. As the handle says, this is CSL's Internet Data Center AS — the network behind its hosting, colocation and cloud business, rather than its consumer access network.

What it's used for

The routing evidence is unusually self-consistent. RIS sees 102 IPv4 prefixes carrying 51,712 addresses, 7 IPv6 prefixes, and 7 observed BGP neighbours. Fifty thousand addresses with only seven neighbours is not a carrier — a wholesale transit business of that address size would peer with hundreds of networks. It is a hosting estate: a large pool of addresses handed out to servers, reached through a small number of upstreams. The reverse DNS confirms it directly. Sampled addresses resolve as idc-27-254-60-5.csloxinfo.com and reverse-203-172-40-5.csloxinfo.net — the operator's own generated hosting PTRs — mixed with customer-configured names on individual servers (ns1.pimjob.com, linux.psquare.co.th). Machine-generated idc- PTRs alongside bespoke customer hostnames is what a shared data centre looks like from the outside.

Notable

• The bulk of the space is drawn from 27.254.0.0/16, announced as dozens of /21s and /22s — the classic pattern of a hosting provider slicing one large allocation into per-rack or per-product blocks.
• CSL operates data centres in several Thai regions, so addresses in this AS are not necessarily in Bangkok even though the company is headquartered there.
• IPv6 is deployed across several ranges including 2404:b1::/32 and 2400:b5c0::/32.
• This is the IDC network specifically; CSL's other business lines sit behind different ASNs, so do not read consumer broadband into addresses seen here.