A mailbox is the place where emails are stored. POP3 and IMAP are protocols which are used to connect your mailbox account to email clients, such as Microsoft Outlook, Mozilla Thunderbird, Gmail, Outlook.com (Hotmail), or smartphones and tablets.
IMAP – Internet Message Access Protocol.
The crucial benefit of IMAP is that you can receive your email on more than one device or email client, because the actual mailbox content remains on the mail server (until they are deleted by the user). The status of emails and folders will be coordinated. Essentially this means any email read on your device will also automatically appear read when you check your account later, no matter which client or device you use. The same can be said for emails deleted, flagged or filed and any folder management.
Naturally nowadays we use many ways to access emails: webmail (via a browser), email clients and mobile devices and IMAP will allow you to seamlessly manage your mailbox from all of these different devices and clients.
- All messages are permanently stored on the server until deliberately deleted and purged.
- All email clients or devices used are synchronised.
- Because emails are on a remote email server you’ll have a limited mailbox size (depending on settings provided and storage purchased). It will be more important to house keep email messages to ensure the numbers retained on the server are kept in check.
- IMAP supports the usage of flags to define the status of the message (i.e.read, replied to or deleted.) These flags are stored on the server, but the various email clients can handle them differently.
- Emails flagged for deletion will remain in your mailbox and may still need to be compacted or purged from within your email client to delete permanently.
- When you send messages from a device they may not be saved to an IMAP Sent folder on the server (some email clients save Sent, Trash and Drafts locally by default). If this is the case you will need to configure the client settings to amend this default behaviour if so required.
Remember: as this will add to the storage space required on the server, be sure to archive emails by moving to a local folder and delete unwanted emails periodically.
POP3 – Post Office Protocol revision 3.
Emails are downloaded to a device and are then tied to that specific device. By default, POP3 deletes mail from the server once it has been retrieved.
You can opt to leave a copy of the message on the server to be downloaded again later if necessary (by another device or email client, for example), but there is no two-way synchronization between your device and your mail server. In effect setting ‘Leave messages on server’ means you are in essence simply creating multiple copies of your mailbox. Mailbox folder management would need to be repeated in each individual email client and when using a different client there will be no indication which email you have already read, deleted, flagged or filed.
- A complete local copy of your emails.
- Very little remote server storage space required (if emails are deleted from the server as they are retrieved).
- Local copies of messages are vulnerable to data loss if hardware fails.
- No remote copy (if all emails are deleted from the server as they are retrieved)
- No synchronization between email clients or devices.
- If using webmail via a browser (i.e. effectively using IMAP) when out and about, make sure you don’t leave your POP3 configured email client open on your main device, or it may download all your recent emails.
If you need to access your emails from multiple computers and/or mobile devices, IMAP is probably best for you.
If you always access your email through one main interface, and you have limited online storage capacity or slow broadband POP3 is probably best for you. Just ensure you back up your emails regularly and preferably not on the same device – in case of total hardware failure.