AS10747 EPIC-HOSTING

EPIC-HOSTING is Epic Hosting, LLC, registered at Verona, Wisconsin — the campus of Epic Systems, the electronic health record vendor. This is not a general-purpose web host that happens to be called Epic. It is the hosting arm that runs Epic's EHR software on behalf of the hospitals and health systems that license it.

What it's used for

RIS observes 24 announced IPv4 prefixes carrying 15,360 addresses, no IPv6, and 8 observed neighbours. The reverse DNS makes the workload unambiguous: every sampled address resolves under epichosted.com, and the labels name Epic's products — a-mychart.et1369.epichosted.com, a-epiccarelink.et0798.epichosted.com, b-epiccarelink.et1532.epichosted.com, plus pauth and access endpoints under access.epichosted.com.

The pattern inside those names is the interesting part. Each host carries an et#### token, and the same token recurs across different product hostnames. That reads as a per-tenant identifier: one health system gets an environment number, and its MyChart patient portal, its Care Everywhere/Care Link exchange endpoint and its authentication front end all live under it. The a-/b- prefixes and a -np suffix seen on one host are the giveaways of paired production instances and a non-production environment beside them.

Notable

Eight neighbours against 24 prefixes is a hosting edge, not a carrier: enough upstreams and peers for resilient patient-facing access, no peering business of its own. The address space is heavily deaggregated into /22s and /23s from four separate parent ranges (64.18.144.0/20, 170.133.208.0/20, 208.56.192.0/20, 45.42.32.0/22), consistent with per-tenant or per-site segmentation across data centres.