DNS history guides

Learn how to identify mail and DNS providers, compare SPF policies and read the dates in a DNS history.

DNS guides · Reviewed 2026-09-24

Guides by record type

MX / MAILMail servers ↗Identify mail providers and gateways from their MX hostnames.NS / DNS HOSTINGNameservers ↗Find DNS providers and compare past nameserver records.TXT / SENDING POLICYTXT and SPF ↗Compare email sending policies and domain verification records.

Dates and coverage

Reading a DNS timeline explains how the 50 observations are selected, what their dates mean and how providers are identified. It also includes an example with Microsoft and OVHcloud MX records.

New to DNS?

Start with how DNS works, then use the record-type reference to distinguish mail routing, DNS hosting, aliases and IP addresses. The about page explains where this tool gets its observations.