Generally speaking, there are three different types of email protocols that are commonly used today. These protocols determine how users interact with their mail on the server and locally on their computer. They are:
- POP – Post Office Protocol – Commonly used by Internet Service Providers (ISPs) to reduce the amount of storage needed for each of their customers. Once the customer has downloaded the email from the ISP’s server, it is normally removed to save space. The common version is 3, aka, POP3.
- IMAP – Internet Message Access Protocol – This protocol allows the user to store all of their messages on the email server. If desired, copies of the email messages may be downloaded to local machines also. Any activity done to the server version of the email appears on all other IMAP-connected devices. For example, if a message is moved to a folder or removed, no matter where the user connects from, they will see the result of the earlier changes.
- Microsoft Exchange – Similar to IMAP, but may also sync contacts, calendars, notes and other data.
One of my clients had been using a POP3 server for many years. Employees had downloaded many thousands of messages to their local machines. The messages that had been downloaded and cleared from the server were only available on the machine which downloaded them. Having recently migrated to an IMAP server, he was interested in having his employees gain access to all the old POP mail from the new IMAP server.
Per my clients request, I did a little investigation into how this might be accomplished. I was truly astonished to find out that through the use of an email client like Apple Mail, Outlook or Entourage, you can easily move mail that had been retrieved via POP protocol to the IMAP server. It turns out, the IMAP server doesn’t know or care that the mail was not originally destined for it’s own server. It treats all email messages alike. I have verified this with Kerio Mail Server and Gmail. Truly amazing!
What does this mean to the casual observer? For those of you have downloaded all the email messages you have received over the years from your POP server, you now have a way to back up your email messages and store them online so they can be accessed anywhere and at any time. To do this, you will need access to an email system that supports the IMAP protocol. If nothing else, create a new Gmail account. Next, get this account set up in your local email utility like Apple Mail, Outlook, Entourage or Thunderbird. Finally, drag the email messages you want to store from their original folder structure on your local machine into the folder structure that exists for your Gmail account. The copying of the messages will take a while and does depend heavily on your upstream bandwidth. Be prepared to wait a while as the data is transferred to the IMAP server.
Use this tip at your own risk as it may go against the Terms of Service of your ISP or other IMAP service provider.