AS10801 REGIONS-ASN-1

REGIONS-ASN-1 is the network of Regions Financial Corporation, the Birmingham, Alabama bank holding company behind Regions Bank, a large retail and commercial bank across the US South and Midwest. RIS sees 29 IPv4 prefixes carrying 23,808 addresses, no IPv6, and 3 observed neighbours.

What it's used for

Regions' own internet edge. The announcement set is unusually clean for a bank: essentially all of it comes out of 205.255.0.0/16, announced as one /19 (205.255.224.0/19) plus a long series of /22s and the /23s they split into. This is the bank's public infrastructure — online and mobile banking, branch and ATM backhaul, mail, partner and payment-network links, remote access — and none of it is resold.

Notable

Three neighbours against nearly 24,000 addresses is the classic enterprise fingerprint, and it is the number that settles the classification. A network this size that was in the transit business would peer with hundreds of ASes. Regions buys from a small number of upstreams for redundancy and carries nobody else's traffic. As with most US banks in this range, the entire footprint is IPv4; there is no IPv6 announcement at all.

Interesting

The deaggregation pattern is a traffic-engineering habit rather than a necessity. Announcing 205.255.100.0/22 and 205.255.100.0/23 together, or 205.255.24.0/22 alongside 205.255.24.0/23, adds nothing to reachability. It exists so specific sites can be steered onto specific upstreams, or so a scrubbing provider can pull a piece of the space during an attack without moving the whole aggregate.