AS9583 SIFY-AS-IN Sify Limited

AS9583 (SIFY-AS-IN) is held by Sify Limited, now Sify Technologies, an Indian ICT company formerly known as Satyam Infoway. Sify was India's first private ISP and today sells enterprise connectivity over a national MPLS backbone, plus data-centre colocation, cloud and managed services. AS9583 is by far the largest AS in this part of the number range.

What it's used for

This is a carrier. RIS shows 2,187 IPv4 prefixes covering 795,648 addresses, 34 IPv6 prefixes, and — the figure that settles the role — 826 observed neighbours. An access network serving only its own subscribers peers with a handful of upstreams; 826 adjacencies means a large downstream customer cone plus heavy presence on the Indian exchanges. Sify runs a national network with thousands of points of presence, and the neighbour count is what that looks like in the routing table.

The eyeball side has not gone away. The largest blocks are a 223.30.0.0/15 and a long run of /20s out of 118.94.0.0/15, and reverse DNS across those /20s resolves address after address to retail.dynamic.sify.net, with 223-30-0-0.lan.sify.net and segment-95-118.sify.net filling in the rest. Retail and dynamic are broadband-pool words. The deaggregation into thousands of small prefixes fits the same picture: many regional POPs with per-region pools, announced piecemeal rather than as clean aggregates.

Notable

• Treat this AS as mixed when geolocating or reputation-scoring. A hit in 118.94.0.0/15 is most likely an Indian consumer broadband address; elsewhere it is as likely to be an enterprise circuit or hosted service.
• The IPv6 deployment is real rather than decorative: a 2001:e48::/32 plus more-specific /48s.
• Sify operates data centres across India, so the AS carries hosted traffic alongside the retail pools.