We often get asked by customers about the differences between IMAP and POP, the two protocols used when accessing your incoming mail. Here’s a brief summary.

First, some background. When someone sends you mail, it doesn’t immediately go to your PC or device, but is sent to an account on one of our mail servers where we hold the message for you. This is where IMAP and POP come in because these are the ways in which you can access the mail from our servers.

In the ‘old’ days, the most popular way of getting your mail was to use the POP protocol. This allowed you to download the mail from the server and store it on your PC or device. This allowed for ‘offline’ working when using the old modem style dialup internet access. You could choose whether to leave the mail on the server, or remove it immediately or later to reduce storage requirements on the server.

One downside of this protocol is that only one device can access the mail using POP at any time – if more than one device tries (eg a PC and a phone) then the unlucky one would be told there was an error and it would usually prompt the user for his email address and password, thinking that one of these was at fault. This wasn’t too much of a problem in the old days when people generally only had one device but now when more and more people have PCs, phones and tablets it’s more of an issue.

Another limitation with POP is that it only downloads from your InBox on the server – this is important if you use both POP and IMAP together because POP can’t see any messages that have been filed away to a folder using IMAP.

More recently, devices default to the IMAP protocol when you set up a new account. Instead of downloading the mail from the server and then deleting it, IMAP keeps the mail on the server and lets you access it ‘live’. One of the great advantages of IMAP is that more than one device can access the mail at a time so you don’t get the errors that POP gives you when there are simultaneous accesses.

IMAP also lets you create folders on the server and organise your mail there. If you use WebMail then you are using IMAP.

Examples of IMAP Webmail offered by Calico UK

Which protocol is best for you depends on how you will use your mail. If you only have one device with lots of storage space (eg a PC) then POP might be best – download your mail to your PC and organise it there. But remember to back your mail up regularly.

If you are out and about a lot, or want to access your mail on several devices (eg PC at home, plus another PC in the office, and phone or tablet when out and about) or only have a device with a small amout of storage (eg a phone) then IMAP would be recommended.

You could also use a combination of protocols to save on storage space on our servers, eg download your mail regularly to your PC using POP, but leave a copy on the server for several days or weeks so that you can still access the most recent messages using IMAP on your phone or tablet.

If you have any questions about setting up your mail then please contact our friendly helpdesk.