Anyone who has worked with email knows this, but that doesn't stop mail users from calling us and asking why a message is late. But hey, what's yet another example? This describes the mail routing a specific message followed.
Received: from [140.160.12.34] by web120819.mail.ne1.yahoo.com via HTTP; Sun, 20 Feb 2011 17:48:33 PST
Received: (qmail 81576 invoked by uid 60001); 21 Feb 2011 01:48:33 -0000
Received: from [127.0.0.1] by omp1039.mail.ne1.yahoo.com with NNFMP; 21 Feb 2011 01:48:33 -0000
Received: from [98.138.88.239] by tm4.bullet.mail.ne1.yahoo.com with NNFMP; 21 Feb 2011 01:48:33 -0000
Received: from [98.138.90.51] by nm24.bullet.mail.ne1.yahoo.com with NNFMP; 21 Feb 2011 01:48:34 -0000
Received: from nm24.bullet.mail.ne1.yahoo.com ([98.138.90.87]) by BAY0-PAMC1-F6.Bay0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675);Sun, 20 Feb 2011 19:37:38 -0800
Received: from mail pickup service by SNT0-XMR-002.phx.gbl with Microsoft SMTPSVC; Sun, 20 Feb 2011 19:37:48 -0800
Received: from SNT0-XMR-002.phx.gbl (10.13.104.140) by BL2PRD0103HT012.prod.exchangelabs.com (10.6.4.137) with Microsoft SMTP Server id 14.0.650.68; Mon, 21 Feb 2011 03:37:54 +0000
Normally these headers are read from bottom up, but this is ordered top down. Translated, this means:
This does show that mail consumers tend to assume two key things:
Received: from [140.160.12.34] by web120819.mail.ne1.yahoo.com via HTTP; Sun, 20 Feb 2011 17:48:33 PST
Received: (qmail 81576 invoked by uid 60001); 21 Feb 2011 01:48:33 -0000
Received: from [127.0.0.1] by omp1039.mail.ne1.yahoo.com with NNFMP; 21 Feb 2011 01:48:33 -0000
Received: from [98.138.88.239] by tm4.bullet.mail.ne1.yahoo.com with NNFMP; 21 Feb 2011 01:48:33 -0000
Received: from [98.138.90.51] by nm24.bullet.mail.ne1.yahoo.com with NNFMP; 21 Feb 2011 01:48:34 -0000
Received: from nm24.bullet.mail.ne1.yahoo.com ([98.138.90.87]) by BAY0-PAMC1-F6.Bay0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675);Sun, 20 Feb 2011 19:37:38 -0800
Received: from mail pickup service by SNT0-XMR-002.phx.gbl with Microsoft SMTPSVC; Sun, 20 Feb 2011 19:37:48 -0800
Received: from SNT0-XMR-002.phx.gbl (10.13.104.140) by BL2PRD0103HT012.prod.exchangelabs.com (10.6.4.137) with Microsoft SMTP Server id 14.0.650.68; Mon, 21 Feb 2011 03:37:54 +0000
Normally these headers are read from bottom up, but this is ordered top down. Translated, this means:
- A message was sent from a computer on campus via a Yahoo mailer (98.138.88.239) at 17:48:33 PST.
- This was processed by another Yahoo mailer (98.138.90.51) at 17:48:33 PST
- And again (98.138.90.87), at 17:48:33 PST
- It was picked up by the Microsoft mailer (10.13.104.140) at 19:37:48
- And forwarded on to an ExchangeLabs server (10.6.4.137) where it came to rest.
This does show that mail consumers tend to assume two key things:
- Mail transit is very fast (where 'fast' can be defined as anything under a minute to up to five minutes depending on the user).
- The Date is when it is received.
Oh, wow, yeah, I go through this ALL the time with my users. You know what they like even less? When I try to explain to them that, by definition, e-mail is an unreliable service. It was right in the original RFC, if I remember correctly. Their eyes just bug out at me. If I'm feeling patient, I slowly, sometimes with illustrations, explain how e-mail works. If I do it right, they end up being amazed that an e-mail message ever gets delivered at all!
Next post: Why email is NOT a file storage and/or sharing system...
I think the old IBM mainframes introduced an intentional delay, so mail always took the same amount of time to get there whether the system was heavily loaded or not.