IMAP vs POP3

This information only pertains to Hurricane Electric's Shared Web Hosting package. There may be different information in our other categories.

What is IMAP?

IMAP is a standard protocol for checking e-mail. You (by using your e-mail client, such as Outlook or Thunderbird) can view just the header information, which includes the sender and subject of the letter, allowing you to decide whether to download the message or not. You can also create and manipulate folders or mailboxes on the server, delete messages, or search for certain parts or an entire message.

What is POP3?

POP3 is also a standard protocol for receiving e-mail. With POP3, your mail is saved in a mailbox on the remote server until you check your mail. When you check your mail, all of the mail is immediately downloaded to your computer and is no longer maintained on the server.

What is the basic difference between IMAP and POP3?

IMAP can be thought of as "remote" e-mail storage, while POP3 can be thought of as a "store-and-forward" service. Ultimately they both accomplish similar tasks, but often one will suit your needs better than the other.

What are the Benefits of IMAP?

Since you can view just the header information without downloading the entire message, you can delete large messages without wasting time for downloading them. Also, because the messages remain on the server, you can access your mail from multiple locations at the same time and ensure that your messages are always available for you. And, since the messages remain on the server, if your computer crashes you don't have to worry about losing your messages. IMAP is generally faster and more reliable, especially with certain email clients such as Microsoft Outlook.

What are the Benefits of POP3?

Since all of your messages are downloaded immediately, after you check your mail at your computer, you do not need to actually be connected to the Internet to read your email. Also, because the messages are downloaded to your computer you do not need to worry about accruing disk usage charges because the messages do not stay on the servers. Just make sure your email client is set to delete email messages from the server after downloading them, or else all your emails will sit there, taking up space, until you use Webmail or an IMAP client to delete them!

What are the Drawbacks to IMAP?

There are few. Unlike POP3, IMAP requires continual access to the server during the time that you are working with your mail.* Also, because the messages are stored on the server, it becomes much easier to go over your disk quota on our oldest servers. And like any new service, there is a slight learning curve to get used to IMAP since most people are used to using POP3.

*Note: Some email clients have an Offline mode which can negate this drawback, effectively keeping a local copy of your email as well as the copy on the server. Please consult your mail client vendor for how to configure this feature if available to you.

What are the Drawbacks to POP3?

The major drawback to POP3 is that it is an older protocol that was designed before people were able to easily send large emails with attachments. Because POP3 downloads all the mail on the server at once, people are occasionally unable to successfully receive their messages because POP3 will get stuck or disconnect when trying to download large messages. To fix this, people will either need to contact tech support or log onto our webmail system to delete the large messages themselves. Also, if you use POP3 and are traveling or check your mail from multiple locations, you will not be able to view any of your old mail because the messages only exist on the computer on which you originally received your mail. Finally, some email clients, such as Outlook, are more prone to certain bugs (such as downloading duplicates of emails) when using POP3 than IMAP.

How do I convert my mail software from POP3 to IMAP?

Changing the way you check your mail from POP3 to IMAP is fairly easy, though it can be a somewhat lengthy process. That said, the good news is that once you do it, your life will become 'much' simpler.

*Note: If you have an IT professional in-house, or even just someone more comfortable with computers, you are encouraged to ask them to perform this process.

No mail software will allow you to simply change from POP3 to IMAP. You need to create a new IMAP profile. This will cause all the mail currently stored on our server to download to your computer again; this is fine, and this 'double download' will only happen once.

You can find specific instructions for how to switch from POP3 to IMAP in several different email clients here (remember to use your domain name as the server, not Boston University's). The process, basically, is this:

Set up a brand new IMAP profile inside your mail software using your existing settings

As stated, no mail software will allow you to simply change from POP3 to IMAP. You need to create a new IMAP profile.

The following settings will remain the same in IMAP as they were in POP3:

   * mailbox username [name@example.com]
   * mailbox password
   * outgoing mailserver [example.com]
   * incoming mailserver [example.com] 

Once the IMAP profile is active, any email still located on the server will download to your computer again; this is fine, and this 'double download' will only happen once.

*Note: Customers using Outlook can find a tutorial here that details setting up IMAP mail.

Move all your local saved folders from your local POP3 profile to your new IMAP profile

You probably have a lot of saved messages on your local mail program: things like your Sent folder, or perhaps folders containing emails from clients, customers, associates, or friends. Converting over to IMAP means no longer having to use those local folders. Simply drag and drop those folders from your 'local folders' area to the new IMAP area. This will cause those folders, and the emails inside them, to be uploaded to our server.

The upshot of this is that you are now able to view these folders from any physical location, using any email program, including Webmail.

Delete the POP3 profile

Once you've completed the mail folder copy and have verified that the copy completed successfully, and then verified again (measure twice, cut once), you may feel free to delete the POP3 profile settings.

That's it! If you have any questions, please contact support@he.net or 510-580-4100. Support is open 24 hours a day, 7 days a week.

Can I use webmail 1 to check my IMAP mailbox? (v2 only)

No. You'll need to use webmail 2. If your server doesn't support webmail2, you'll need to either delete the mailbox and recreate it, or upgrade to a new server via the HE.net admin page.