AS10617 SION S.A

SION S.A. is an Argentine Internet provider, in the market since 1995 and headquartered in Buenos Aires, selling access to homes and businesses across a very wide spread of towns in the country's interior. It absorbed the early Argentine ISP UOL Sinectis in 2010, which is why two brands share this one AS.

What it's used for

This is an eyeball network, and the reverse DNS says so plainly. RIS observes 216 IPv4 prefixes carrying 54,272 addresses and two IPv6 prefixes, 2803:9780::/32 and 2803:6380::/32, against 6 observed BGP neighbours.

The sampled PTRs are subscriber-pool naming across several access technologies: cablemodem-200-59-108-5.madryn.sinectis.com.ar and cmts1.alvear.mendoza.sinectis.com.ar (cable/HFC, with the CMTS itself visible), ont-200-59-78-5.trelew.sinectis.com.ar (fibre to the home), dial37-5.sion.net (the dial-up era, still named), and generic host-200-81-184-5.sion.net pools. Every one carries a locality label — Puerto Madryn, Trelew, Alvear in Mendoza — which is how a provider with hundreds of small-town footprints organises its space.

Notable

216 prefixes for 54,000 addresses is the giveaway: an average block size well under a /24-and-a-half. That fragmentation is not untidiness, it is the shape of a provider that grew by lighting up one locality at a time, often over cable plant owned by regional operators it partnered with, rather than by getting one large allocation and subdividing it centrally.

Interesting

sion.com, sion.net and sinectis.com.ar all appear inside the same routed space — a merged ISP rarely renumbers, and the acquired brand's reverse zone can outlive its logo by well over a decade.