Date stamp vs Received Date

Hi - I wonder if anyone has any knowledge about this date stamping anomaly.

I have a client who sent out an email on Wed December 15 and for the most part it appears to have been received immediately.

However one of their recipients complained to them that she received the email on Saturday December 18 even though the Sent Date/Time stamp header on her email clearly shows Wed December 15.  She was confused about this as she did receive other emails on Wed 15 Dec.

What might be the reasons that could cause a delayed delivery of an email - still with the 'correct' Sent Date in the header?

neilphillips, 5 years ago

Hi Felisimina,

I think your question is basically "how come emails don't always get received straight after they're sent?" (if it's not, then apologies).

The sent date refers to the time the server sending the email sends it, so.. that's fixed, and has nothing to do with the date (or time zone) of the receiver.

The server sending the email will try and deliver it, and if there's a problem will (depending on how it's configured) try again after, say, an hour, or half a day, or 2 days, until it gets delivered to the receiving server, or until it gives up (again, depending on how it's configured).

So.. if the receiving server had a temporary failure (could be just a couple of seconds) then the sending server might not have retried again for several hours or days. Other emails send to this same receiving server at any other time on that day, might well have been received perfectly normally.

Also, sometimes, the sending server has a queue of emails, so although the 'sent date' is already fixed (the user has already sent the email) actually they're just queued up waiting to be dispatched. The sent date is just like you writing the date and time on a letter before you drop it in the letter box - with no idea when the postman will show up.

There's more detail on how it actually works here:
http://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol

People always seem confused (especially nowadays) that email isn't instant.

Cheers, Neil

P.S. most mail clients will let you see the sent and received dates for emails as two separate columns, you'll notice that it's fairly common for there to be quite a bit of lag.

felisimina, 5 years ago

Thanks Neil - that's a brilliant response and very helpful!

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