How do you trace message hops with headers?

Tracing message hops via Received headers:

Reading order:

Start at bottom (oldest). Read upward (newest). Each Received header is one hop. Follows the message path.

Header components:

from: Sending server. by: Receiving server. with: Protocol used. timestamp: When received.

What to look for:

Each server in the chain. Time between hops. Any delays or gaps. Where authentication happened. Internal vs external servers.

Troubleshooting use:

Identify where delay occurred. Find which hop rejected. Trace through gateways. Verify routing.

Example pattern:

Originating server > gateway > internet > receiving MX > final mailbox.

Received headers are breadcrumbs. They trace the exact path the message traveled.