Level: Beginner
Tracing the full technical path a message travels reveals the multiple checkpoints where deliverability can succeed or fail along the way.
The Sending MTA Initiates the Connection
Your mail transfer agent establishes an SMTP connection to the recipient's mail server, beginning with a handshake that includes identifying information about the sending server.
Authentication Checks Happen During Transit
The receiving server checks SPF, DKIM, and DMARC alignment during or immediately after the SMTP transaction, before deciding whether to accept the message at all.
Filtering and Placement Happen After Acceptance
Once accepted, the message passes through spam filtering, reputation scoring, and content analysis layers that determine its final destination within the recipient's mail client.
Next step: Use the Server Status Checker to check the current status and response behavior of your sending mail server as the starting point of this journey.