Email Network Security Blog

IMAP and the Mobile Device

All the smart phones out there today like the Apple Iphone and Nokia N-series have the ability to access email services. For receiving mail, there are two methods (or protocols): IMAP and POP3. It is important to know that IMAP is the newer and more capable protocol and the one you definitely want to use with your mobile device. I will explain why.

POP3 views the mailbox as a simple mail drop. Your mail client picks up mail from the mailbox, deletes it from the mailbox, and stores the authoritative copy locally on the client machine. With IMAP, your client views the messages on the server and downloads the parts it wants, leaving the master copy on the server. With IMAP, the server copy is authoritative and the local client copy is a “replica”. This has several implications.

With IMAP, multiple clients may simultaneously connect to the same mailbox: Using IMAP, you will see the same set of messages in the same set of folders as on any other computers connected to the same mailbox. This means that you don’t have to sync your phone to your computer. Your inbox is automatically in sync because it is server-based.

Partial MIME message-part fetching: This is probably the most compelling reason to ditch POP3 and start using IMAP on your phone. With POP3, you have no choice but to download an entire message from the list of available messages in your inbox. With IMAP, you can download the body separate from the attachments. This comes in handy when someone sends you a 20MB attachment.

No need to back up the mailbox: If you have a good email provider like Sentinare Messaging Solutions, Inc, then you can be assured that your mailbox is being backed up regularly, with snapshotted backups for the past 15-days. With POP3, the mail that is read by your client is typically deleted from the server, but with IMAP, which is server-based, the messages and folders stay on the server, where they are backed up by your email provider.

Message state information: With IMAP, messages that are marked “read” or “unread” are marked the same way on all IMAP clients viewing the same mailbox. IMAP also supports user-based tags, which are useful for categorizing email.

Online folders: IMAP has support for multiple nested folders stored on-line. POP3 has no concept of folders other than the one inbox.

Server-side searches: IMAP supports running searches on the server. This mechanism avoids requiring clients to download every message in the mailbox in order to perform these searches.

Switch all your clients to IMAP today because it is a big improvement over POP3 and you will be able to take advantage of all these benefits. If you don’t have a decent IMAP provider, go here: Sentinare Messaging Solutions, Inc.