IMAP vs POP3

This document helps you decide between IMAP and POP3 when connecting your CertMail to your e-mail client to your CertMail.

Document 1017  ¦  Last updated:  05/06/2014 ACN

Click the tabs below for more information on the differences between IMAP and POP3.

IMAP is a server‑based e‑mail technology that leaves all your e‑mail messages and mailbox configurations entirely online.  By taking this approach to e‑mail and folder storage, all e‑mail folders become completely portable — requiring no additional configuration on additional computers beyond the basic Outlook setup.  Because this type of connection is entirely dependent on the server, increasing the complexity of support calls, fewer e‑mail providers actually offer IMAP support.  By the same token, since your e‑mail messages and mailbox configurations are entirely online with IMAP, it's best for you to have a stable, high‑speed connection to reduce the likelihood that you'll receive errors while managing your e‑mail.

Since IMAP leaves your e‑mail messages online instead of downloading copies of your messages (like POP3), deleting the message in Outlook or in CertMail's Web Mail interface deletes the message entirely.

In a practical sense, this type of setup offers one key benefit.  Namely, folders you create with IMAP are duplicated in your e‑mail on the server.  Then, when you set up another IMAP connection to the same mailbox from another computer, the folder structure remains intact.  If you're regularly moving from computer to computer or simply need access to the same folder structure no matter where you access your e‑mail, IMAP is probably the best solution for you.

One final thing to consider though, before accepting IMAP as your preferred e‑mail connection, is the method you must use to delete e‑mail when you use an IMAP connection.  Many computer users have become accustomed to the concept of selecting a bunch of items they wish to delete and sending them to the Deleted Items folder, the e‑mail version of a Windows Recycle Bin.  IMAP does not use the Deleted Items folder as a temporary holding place for messages pending deletion.  Instead, it places a strike through the e‑mail message to indicate that it has been deleted, and when you're ready to purge it from your mailbox entirely, you must indicate that with your e‑mail program.

In all of the various versions of Outlook, you can purge your mailbox of IMAP deleted items by clicking Edit, Purge Deleted Items from the menus.

In short, if you find yourself regularly accessing your e‑mail from different computers, have a high‑speed Internet connection, and are comfortable learning a slightly different workflow for deleting messages, IMAP is your solution.

POP3 is a client‑based technology that stores all your e‑mail messages and folders on your computer.  Since your e‑mail and folders reside on your personal computer, all that's required with POP3 connections is a quick connection to your mailbox on the part of your e‑mail client to download any new mail that's arrived.

In order to maintain the portability of your e‑mail, you must configure your e‑mail clients (such as Microsoft Outlook or even your mobile device) to leave a copy of the message on the server.  If you're unsure how to enable this feature, consult the manual that came with your software or device, or contact a local technician.

Unlike IMAP, this configuration does not allow you to maintain the same folder structure if you set up your e‑mail on another computer.  However, it still allows you to download identical copies of your mail messages on as many computers as you like.

In addition, since POP3 only requires you to connect to your mailbox for a short period of time to download new messages, it's not nearly as important for you to have a stable, high‑speed connection as it is with IMAP.  If you use a dial‑up or satellite connection to the Internet, POP3 is definitely the best option for you.  But even if you have a high speed connection, you may still want to consider using POP3 as your connection type.  POP3 — with it's stability on weaker Internet connections — has seen more widespread adoption amongst e‑mail users and has consequently become the more familiar approach to e‑mail for most people.

In short, if you tend to use the same computer to manage your e‑mail all the time or have a slower, weaker Internet connection, POP3 is your best choice.  And even if you have a stable, high speed connection, POP3 may be the best solution for you thanks to its greater overall stability and familiar methods for managing e‑mail.

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