I keep planning to add this to the documentation, but I thought I'd write it up quickly as a blog post.
One recurring question we have get is people asking the best way of migrating accounts from an existing system to a new FastMail family/business package. Basically there's two main approaches:
The documentation below helps explain these two approaches, and the other tools we provide to help you migrate accounts from other services to FastMail.
The main advantage of this process is that it's a decisive cut-over from the old system to the new. The disadvantage is that after you change the MX records, you have to run the IMAP Migrate for all users so they get their existing email at FastMail, and if any users use email software (eg Outlook Express, Thunderbird, etc), you have to update all of them to use the new server names at once after the MX change over.
The main advantage of this process is that it allows you to move one account at a time from the old system to FastMail giving you time to gradually move users. For each user, you can migrate them, update that users email software to access our servers, and generally ensure that each transfer is smooth and complete, before moving onto the next user.
Signup your family/business at FastMail (just follow the links near the bottom of the login screen at http://www.fastmail.fm)
During the signup, add any domains you want to use, even if they're currently hosted externally
For each user you want to migrate, repeat the following steps:
Once you've done all accounts, change the MX records to point to us, completely removing the old site from handling your email. Everything moved over, no downtime, no lost email, no interruption
The forwarding tunnel (previously documented here) allows you to forward email from an existing service to an account with the same name at FastMail. eg Say you have the account email@example.com at an existing service. You want to create your account as firstname.lastname@example.org at FastMail, but how do you forward from the old email@example.com account to the FastMail firstname.lastname@example.org account while the DNS still points to the old server? This is what the forwarding tunnel solves.
It basically gives an extended email address syntax that you can forward email to, which will deliver to our servers, and then decode to the account name. There are 3 encoding options because some providers are limited by what characters you can put in an email address to forward to.
To forward email to the FastMail account email@example.com, you can forward to any of these 3 addresses:
The Options -> IMAP Migrate feature allows you to migrate email from an existing IMAP server to FastMail. During the migration, it will attempt to preserve the existing folder structure, emails and email state (eg seen or unseen) from the existing server. The migration may take some time depending on the size of the account it's migrating. The migration will run in the background, and will email you when it's completed with a status report of what it did and if it encountered any problems. In general if it does encounter problems, it will try several times on a folder before giving up and moving to the next folder.
The most common reason for problems are: