Source originale du contenu
Email perfectly embodies the spirit of the internet: independent mail hosts exchanging messages, no host more or less important than any other. Joining the network is as easy as installing Sendmail and slapping on an MX record.
At least, that used to be the case. If you were to launch a new mail server right now, many networks would simply refuse to speak to you. The problem: reputation.
Email today is dominated by a handful of major services. GMail boasted 425 million active users back in 2012. Outlook.com has at least 400 million users. It's become increasingly unusual for individuals or businesses to host their own mail, to the point that new servers are viewed with suspicion.
Earlier this year I moved my personal email from Google Apps to a self-hosted server, with hopes of launching a paid mail service à la Fastmail on the same infrastructure. I've done this before, and this server was configured perfectly: not on any blacklists, reverse DNS set up, SPF, DKIM and DMARC policies in place, etcetera. (Side note: mail-tester.com and Port25 are great for checking your setup.)
I had no issues sending to other servers running Postfix or Exim; SpamAssassin happily gave me a 0.0 score, but most big services and corporate mail servers were rejecting my mail, or flagging it as spam:
- Outlook.com accepted my email, but discarded it.
- GMail flagged me as spam.
- MimeCast put my mail into a perpetual greylist.
- Corporate networks using Microsoft's Online Exchange Protection bounced my mail.
The standard advice from all of the above boiled down to this, from Microsoft's Postmaster Troubleshooting page:
IPs not previously used to send email typically don’t have any reputation built up in our systems. As a result, emails from new IPs are more likely to experience deliverability issues. Once the IP has built a reputation for not sending spam, Outlook.com will typically allow for a better email delivery experience.
How to build a reputation for not sending spam when they're already flagging, bouncing, or deleting my mail was unclear.
In the end, I gave up and switched back to Google Apps. It felt like defeat. This isn't how the internet is supposed to work. As we continue to consolidate on a few big mail services, it's only going to become more difficult to start new servers.