Mapping Swiss Municipal Email Providers

This project offers a comprehensive map of approximately 2,100 Swiss municipalities, detailing which providers manage their official email systems. By analyzing public DNS records and network signals, the map categorizes providers by jurisdiction, shedding light on the digital sovereignty landscape. The significance of this map is underscored by the implications of the US CLOUD Act, which allows US authorities to access data stored by US-based providers, regardless of its physical location. To determine the email provider for each municipality, the project uses a combination of 11 signals, including DNS records, SMTP banners, ASN lookups, and a Microsoft API endpoint. The results are classified by provider type and scored for confidence. It's important to note that while DNS records reveal mail routing and authorized senders, they don't necessarily indicate where data is stored. The project is open source, with code and data available on GitHub, inviting contributions and corrections from the community.