The Date header is not the hop time

Date is the sender clock

The Date header is a timestamp inside the message. The software that created the message set it. It can match a real send, or it can be hours off because a laptop clock was wrong. It is not a log line from your mail gateway.

If Date is missing, write “Date not in this copy.” Do not fill it from a Received line.

The hop time is on Received

The Received line added by your provider includes the time that server accepted the message. That is the arrival time at the boundary you operate. Later internal hops have their own times. Use the provider hop when you say when the message reached you.

A gap between Date and that hop is a fact. It can be queueing, a clock skew, or a Date value you should not treat as arrival. The gap alone does not explain which.

What to write down

File Date, the provider Received timestamp, and which host added that Received line. Label them. A sentence that says “received at” has to name the hop, not the Date header.

Lab: 09:00 in Date and 10:40 at the gateway

A saved lab message shows Date: Mon, 2 Nov 2026 09:00:00 +0000. The Received line added by mx.example.org says Mon, 2 Nov 2026 10:40:11 +0000. A draft says the message arrived at 09:00.

The note quotes 09:00 as Date and 10:40:11 as the mx.example.org hop. Arrival at that gateway is 10:40:11 UTC. The draft sentence is replaced. The gap stays in the note without a guessed cause.

Date: Mon, 2 Nov 2026 09:00:00 +0000
Received by mx.example.org: Mon, 2 Nov 2026 10:40:11 +0000
write: Date 09:00, hop 10:40:11
not: arrived at 09:00