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@kaustavha
Created November 4, 2019 17:33
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Various smtp mail server cross connection performances

I checked mail delivery from 3 servers to google. All mail is from hi@kaustav.me

gmail with outbound server set as zoho delivered in 0 seconds. gmail to gmail with from set to zoho

Message ID	<CABaOn_z82JMJsDX62fTQ0vG76HPVTn60iVEDxD1GCzEQVy0foA@mail.gmail.com>
Created at:	Mon, Nov 4, 2019 at 12:17 PM (Delivered after 0 seconds)
From:	Kaustav Haldar <hi@kaustav.me>
To:	Kaustav haldar <kausthal@gmail.com>
Subject:	SE opportunities[HN Who's Hiring 11/2019]

Directly from zoho to gmail:

Message ID	<16e376eb1a9.117baa727217582.222190604686344840@kaustav.me>
Created at:	Mon, Nov 4, 2019 at 12:20 PM (Delivered after 38 seconds)
From:	kaustav <hi@kaustav.me> Using Zoho Mail
To:	kausthal <kausthal@gmail.com>
Subject:	SE opportunities[HN Who's Hiring 11/2019]
DKIM:	'PASS' with domain kaustav.me Learn more

Via apple mail configured to use zoho for outgoing smtp server:

Message ID	<7A73B71A-7649-4FF9-BAD7-44C5E7712E2C@kaustav.me>
Created at:	Mon, Nov 4, 2019 at 12:19 PM (Delivered after 267 seconds)
From:	kaustav haldar <hi@kaustav.me> Using Apple Mail (2.3594.4.19)
To:	kausthal@gmail.com
Subject:	SE opportunities[HN Who's Hiring 11/2019]
DKIM:	'PASS' with domain kaustav.me Learn more

Guesses:

  • Google heavily optimizes for mails within it's infrastructure. Lack of DKIM and SPF is worrying but speed is impressive and it seems to circumvent the classical internet infra.
  • Zoho on site is a direct zoho server to google push. The mail still needs to be validated by googles servers.
  • Via apple mail we incur network and verification latency twice but 267 is really really bad but at least we still retain valid dkim and spf records
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