What is an Email Protocol?
An email protocol is a set of rules that enables servers of different makes and operating systems to communicate with each other for the purpose of transferring emails to and from one another. Protocols are widely used in networking, but three common protocols are primarily used for email.
- POP or POP3: Post Office Protocol (version 3)
- IMAP: Internet Message Access Protocol
- SMTP: Simple Mail Transfer Protocol
Incoming Email Protocols
POP and IMAP are the two protocols commonly used for incoming mail. What protocol is used is determined when you set up the mailbox in your mail client, not by the server. You can use either protocol on most devices, although some older software or devices may only support POP.
POP3
POP, or Post Office Protocol, retrieves messages from the server and stores them on your local storage. By default, a POP account checks for new mail in your Inbox, downloads the latest messages, and then removes the email from the server. Most modern email clients allow you to leave a copy on the server, but you may need to locate the option in the mail client settings. However, this can cause disk usage issues, as deleting mail from the mail client's POP account does not remove it from the server, causing email to accumulate on the server over time.
- POP3 Advantages: The advantage of checking emails with POP is that you aren’t limited by the space allocated to that mailbox on the server side, since the messages are typically removed from the server after they are downloaded.
- POP3 Disadvantages: The primary disadvantage of using POP to check email is that you will only have an archive of your messages and folders on a single device. If you have multiple devices set up as POP, only the first device that receives the email will download a copy of it, as the email will then be removed from the server before the other devices can access it. If you check your emails from multiple computers or devices (such as an iPhone), then you will want to set up your email with IMAP. You can set your POP account to leave a copy on the server, but you will need to monitor your disk usage on the server to ensure old mail is getting deleted from the server. Also, a POP account will not have access to other folders in your mailbox. If you use email folders, you will want to use IMAP.
IMAP
An IMAP email account stores messages on the mail server and syncs between all other IMAP accounts connected. It also allows you to create folders and access them from any location.
- IMAP Advantages: The primary advantage of checking emails with IMAP is that it provides a central storage location for all your mail, allowing your archives to be accessed from any computer with an internet connection. This is beneficial if you are checking from multiple computers or devices (like an iPhone). It means that any email read, moved, or deleted on one device is reflected on all other devices, making it easier to manage your account from multiple locations. You will also be able to access all the folders set up in your mailbox (called IMAP folders for this reason).
- IMAP Disadvantages: The main disadvantage of checking email with IMAP is that you are limited to the allocated storage space on the server for that specific email account. If you are checking email from a single computer most of the time and/or regularly receive large attachments, you will want to consider using a POP account instead.
Conclusion
Use POP if you only ever check your emails from one device and don’t use mailbox folders. Other than that, you should be using IMAP. You can configure POP to work like an IMAP account, but unless you are comfortable adjusting the settings on your devices, it is recommended to use IMAP instead.
Outgoing Email Protocols
Deciding on an outgoing protocol is easy. There is only one, SMTP (think Send Mail To People).
Bonus Pro Tip
One option to utilize both POP and IMAP is to set up most of your devices as IMAP, but configure one device (preferably a desktop) as POP, setting it to leave a copy of mail on the server and never delete it. This will enable you to manage your email from any device and organize your mail into folders. However, creating a POP account will make a copy of all your mail, allowing you to use it for backup purposes. This could be helpful if you need to retain emails for an extended period. You can delete them from the server, but keep a local copy for future reference.