I allude to this tutorial several times in the onboarding guides.
In a nutshell: your business email e.g. media@mybusinessname.com should not be hosted by your servers but by a redundant, reliable service like Google Apps for Business or Microsoft Hosted Exchange.
Why? So that if shit hits the fan, or in a more typical scenario - you reboot your server, you won't bounce emails. Bad for business.
Sort it out! It's very, very easy and I'll walk you through setting it up (it's mainly DNS config).
Link:
Password: stmrocks
I think I love you a little bit Zeno, All of your guides are amazing.
Back in the day, Google used to give out business email/apps accounts for free.
You can probably still find people with several of these accounts which you can buy which may make it cheaper than buying off of Google.
For example, I had (and still have) a few Google Apps for Domains accounts with up to 2000 users, domains that can be hosted and managed. Now this would cost quite a hefty sum!
Super helpful being...Zeno