Migrating from third-party providers to Office 365 – POP3 Email

December 9, 2012 by Peter O'Dowd in IT Infrastructure, Technical Documentation


Part 2: IMAP4 Example 1

Part 3: IMAP4 Example 2


POP mailbox specifics

The provider I will illustrate here is typical of most POP providers. Its capabilities are detailed in the following table.

Capability Example POP provider
Domain name suffix Fixed, cannot be changed and defined by the provider. For example, tailspintoys.com
IMAP capable NO
Admin account with Full Access NO
Export org address book NO
Export Contacts NO
Export Calendar NO

To summarize the table, every mailbox has the namespace of the provider, and these are simple mailboxes containing just an Inbox. It is not possible to export address books, nor is the customer provided with a single account with permission to access all mailboxes. For the purpose of this blog, I’ll give this POP email provider the fictitious name Tailspin Toys (tailspintoys.com). Tailspintoys provides POP mailboxes that cannot be accessed via the IMAP protocol. Therefore there are two options for migrating these POP mailboxes to Office 365:

  1. Each user logs in to the Office 365 mailbox and adds the POP mailbox as a connected account.
  2. Each user logs in to the POP mailbox using the Microsoft Office Outlook client, saves POP mail as .pst files, and then connects Outlook to Office 365 and exports the .pst files into the Office 365 mailbox. (For more information, see How to manage .pst files in Microsoft Outlook and Use Outlook to Move Data Between Accounts).

In this blog, I’ll describe the first method – using connected accounts. It is worth noting that any business using Tailspin Toys’ POP email will almost certainly have fewer than 10 mailboxes. Typically, a complete migration can be performed in less than an hour by manually logging in to each Office 365 mailbox and creating a connected account for Tailspin Toys’ POP mailboxes. Typically, these POP providers have mailboxes in the provider’s namespace. The Tailspin Toys POP mailboxes are in the @tailspintoys.com namespace; when a customer moves to Office 365, they will have registered their own namespace with their domain registrar. It is recommended that both namespaces – @tailspintoys.com and their own namespace – are concurrent for a period to allow for any recipients who might reply to an old mail item sent from the Tailspin Toys email address, and that users should set their default reply address for ALL mail to their new custom address.

Example of simple POP provider Comcast

Add a connected account in Office 365

  1. Open the mailbox in Office 365.
  2. In the Office 365 mailbox, click Options and then select See all Options.

  3. Select Connected Accounts and then click New. The following dialog box appears.

  4. Type the user’s @tailspintoys mailbox name and password, and then click Next. Briefly wait for the following screen to appear.

  5. Click Finish.

That’s it! The POP mailbox is now configured as a connected account in the Office 365 mailbox.

The connected mailbox will now appear in the Connected Accounts dialog box. Email from the POP Inbox folder will now be copied into the Office 365 mailbox. Connected accounts are synchronized once per hour to Office 365.

Setting the default reply address

If you set the default reply address to Automatic, when a user replies to a message, Outlook Web App will automatically set the reply address to match the account through which the message was received. Users can also change the reply address on individual messages as needed. For a migration where the Tailspin Toys mailbox typically will be discontinued after a period of time, it is recommended that the users configure the default reply address to be their new Office 365 mailbox address; e.g., spencerl@treyresearch.com.

For further details on configuring connected accounts, see Getting Started with Connected Accounts.

Continue to Part 2: IMAP4 Example 1

Part 3: IMAP4 Example 2