Reading email headers

Headers are evidence. Received fields record hops, Authentication-Results records receiver authentication conclusions, and fields such as Return-Path, Message-ID, From, Date and DKIM signatures expose message identity and processing.

Read the path correctly

Trusted systems prepend Received fields, so analysts normally reconstruct the route from the bottom upward while treating untrusted, sender-supplied fields cautiously.

Authentication

Do not stop at seeing the word pass. Identify which domain passed SPF or DKIM and whether that identity aligns with the visible From domain for DMARC.