Email Server – Should You Run Your Own MTA?

emailemail-server

I need to send a large volume of emails, roughly 60.000 per week. At the moment we outsource this service to a third party, and we expect to double our volume within the next 6 months.
Since the service is starting to be too expensive, I was thinking about setting up our own MTA.

Our own SysAdmin told us it is not difficult at all to have our own MTA, but I'm afraid he might have oversimplified this.

Is it difficult to handle a MTA? Should I be afraid that my MTA will lose the company mails? Should I stay with a third party service?

p.s: The emails have been collected respecting the local legislation on privacy, so no spam.

Best Answer

There should be no problems in doing it yourself, however, you need an experienced sysadmin, or a sysadmin willing to learn something new. It's not as easy as just running another daemon and opening a port in the firewall.

I run an MTA for personal projects on a VPS, and while you of course need high availability and be able to handle way more load, the general setup would be pretty much the same. Some general advice:

  • Be sure not end up with an open relay, you'll get blacklisted
  • Read up on how to avoid the dreaded spam folder
  • Make sure the correct MX records are in place
  • Use a subdomain for your send only MTA (mailer.example.com)
  • Use correct mail headers, from: and reply-to:
  • Use DKIM for signing mail (helps avoid spam also)

EDIT:

I forgot two important points (thanks symcbean):

  • SPF, to restrict mail from your domain to specific IP or ranges
  • Intelligent bounce handling; configured to talk to your mailing list app (removing dead addresses etc.)
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