A POP Server is a mail server that has implemented Post Office Protocol (POP) to enable retrieval of messages by email applications.
There are two primary protocols implemented on mail servers to allow third-party email applications to retrieve messages from the server. These two protocols are Post Office Protocol (POP) and Internet Message Access Protocol (IMAP).
According to Wikipedia, POP1, as the first version of Post Office Protocol is known, was released in 1984, and was quickly supplanted by POP2 just one year later. POP3, the only version of Post Office Protocol that is still actively used on the Internet, was specified in 1988 and updated as recently as 1998. A new edition of Post Office Protocol, POP4, has been informally proposed, but no progress on developing the standard has been made since 2003.
Frequently Asked Questions
How are IMAP and POP different?
POP is designed to copy email from the mail server to a webmail application or email application installed on a device. In most cases, the email is then deleted from the server. Therefore, when you use POP to access your email, you are effectively limited to accessing that account from a single webmail application or device. If you use a webmail app, such as Gmail, this isn't a huge problem since you can log in to the same webmail application from any device you use. However, if you use an application installed on a specific device, such as Microsoft Outlook, and download new email to that device, you won't be able to access the same email from a different device.
IMAP was developed with today's multiple-device world in mind. IMAP leaves your email on the server so you can log into the same account using IMAP from multiple devices, and the changes you make on one device are shown on all of the devices.
Basically, the difference between IMAP and POP is that when you use IMAP any changes you make in your email application are mirrored on the mail server, and appear in every application or device you use to access your email. When you use POP, the changes you make in your email application are limited to that application and aren't mirrored on the mail server.
If I can use either IMAP or POP, which should I use?
In the majority of cases, it makes sense to use IMAP. Several factors have to coalesce for it to make more sense to use POP:
- You only use one device to check your email.
- Your email service provider has a cap on the amount of disk space you can use for email storage.
- You have more storage space available on the device you use to check your email than what your email service provider offers.
- You are concerned that you will need to store more email than your service provider will allow.
If all of those conditions are present, then it makes sense to go with POP for checking your email. However, if any of those conditions aren't present, you would be better off coming up with an email archiving solution to use when your inbox gets too full, and sticking with IMAP for accessing the mail server.