✉️

Email Delivery Flow

Simple

Free preview · 2 of 5 steps

Email: a chain of SMTP servers

Email delivery involves multiple systems: 1. MUA (Mail User Agent) — Outlook, Gmail 2. MSA (Mail Submission Agent) — accepts from MUA on port 587 3. MTA (Mail Transfer Agent) — routes between servers on port 25 4. MDA (Mail Delivery Agent) — stores in mailbox 5. MUA reads via IMAP/POP3

Each hop adds a Received: header — your forensic trail.

Packets in motion — click to inspect:

1 / 2

Space to play/pause · ← → to step