August 14, 2004

Today POP3 is the most popular protocol used to retrieve email from a mail server. Most of the ISPs in Pakistan provide free POP3 email accounts. However, the majority of users prefer web-based email accounts. Undoubtedly, web-based email is a convenient alternative to POP3, however, there are other alternatives such as IMAP, which is the focus of this article.

IMAP stands for Internet Message Access Protocol. IMAP once stood for “Interactive Mail Access Protocol”, but the name was changed in 1993. IMAP is an open standard, and is a functional (but incompatible) superset of POP. Like POP3 email, IMAP works with email clients. You can use Microsoft Outlook Express, Netscape Messenger, Thunderbird, Eudora, The Bat!, etc.

IMAP was originally developed in 1986 at Stanford University to overcome the limitations of POP3 protocol.

Limitations

POP3 provides no support for organizing mail into folders at the remote server end (remote folder manipulation and multiple folder support) — just like you can create new folders in email clients — and can organize downloaded e-mail messages.

POP3 works well for people who want to keep all of their mail on one computer but is not good for those who access their emails from different computers or other devices at the same time or even at different times. POP3 was never designed to be an online messaging protocol and it simply doesn’t have the functionality needed for high-quality online (or disconnected) operation and primarily for this reason, POP3 is slowly giving way to a newer protocol called IMAP4, which is the current version of IMAP.

IMAP allows email clients to connect to mail servers and remotely manage messages as well as mailboxes (as if they were local) without the need to download their emails locally.

The concept behind many web-based email services (email services which enable you to access your e-mail via a web browser, such as Hotmail or Yahoo! mail) is also based on IMAP.

According to “The IMAP Connection” , key goals for IMAP include:

— Be fully compatible with internet messaging standards, for instance, MIME

— Allow message access and management from more than one computer

— Allow access without reliance on less efficient file access protocols

— Provide support for online, offline, and disconnected access modes

— Support for concurrent access to shared mailboxes

— Client software needs no knowledge about the server’s file store format

Modes

There are three different paradigms for accessing remote mailboxes, and IMAP provides good support for all for all three modes:

1. In “offline” operation, the e-mail client or “Mail User Agent” (MUA), fetches messages from a remote mail server to the local machine, and then deletes them from the server.

2. In “online” operation, messages are left on the mail server and manipulated remotely by client programs — possibly more than one at a time, and probably more than one at different times.

3. In “disconnected” operation, a client connects to the mail server, makes a “cache” copy of selected messages, and then disconnects from the server, later to re-connect and re-synchronize with the server. The user may then operate on the message cache “offline.”

Advantages

IMAP shows significant improvement over POP3 in many arenas and is definitely the superior protocol. IMAP offers you more tools to manipulate your mailboxes and messages on the server. The advantages of IMAP over POP3 include:

With IMAP, in both online and disconnected access modes, mail is left on the server, which is important when you use different computers or other devices (even all at the same time) to access the messages. All the emails can be kept in one central place. You can read your e-mails whether you are at home, at the office, or traveling around the world

IMAP has constructs to permit online performance optimization, especially over low-bandwidth (for example dial-up) links. These include the ability:

— To fetch the structure of a message without downloading it

— To selectively fetch individual message parts

— To use the server for searching in order to minimize data transfer between client and server

This mail protocol can manipulate persistent message status flags (flag is meta-data associated with message for instance, seen flag is used to keep track of which messages have or have not been read). These include standard flags such as “Seen”, “Deleted”, “Answered”, as well as user-defined flags.

IMAP can access and manage multiple mailboxes and folders. This includes the ability to name and access different incoming and archive message folders, but also the ability to list, create, delete, and rename them. These mailboxes can be on the same server or on different servers.

An IMAP client may allow you to see them at the same time, and move messages from one to the other. IMAP has the ability to “append messages to a remote folder” which means that you can save messages to an archive folder, or even from an archive folder back to one’s inbox. In IMAP version 4, there is also “support for folder hierarchies”, which allows nesting collections of folders.

IMAP will also allow you to synchronize your mail folders between your local computer and the remote IMAP server. It can also support concurrent updates and access to shared mailboxes. This capability is useful when multiple individuals are processing messages coming into a common inbox. Changes in mailbox state can be presented to all concurrently active clients via IMAP.

IMAP is suitable for accessing non-email data; such as NetNews, documents. This is handy for uniformly accessing different classes of information.

IMAP provides security and privacy for accessing emails. Encryption for passwords and e-mails can be used. You can work on a shared computer and still keep your privacy because your e-mails are on the remote server.

Start using IMAP

Most of the ISPs in Pakistan don’t provide IMAP access to mailboxes. Some ISPs do offer IMAP access to e-mail, but very few ISPs tell users about IMAP. To check whether an ISP provides IMAP support is often very easy: If you use the email account provided by your ISP, simply select IMAP instead of POP3. Perhaps you will be able to access email. There is no mention of IMAP on BrainNET , but I selected IMAP and it worked.

Another ISP supports IMAP and tells about it. Also check out .

Many web hosting providers also offer IMAP access to mail. If you wish to purchase a Web hosting package, choose one which provides IMAP access to email. My web hosting provider PakHost offers IMAP access, and I am pretty impressed with IMAP. There are many other web hosting companies - and many don’t mention that IMAP is supported.

Nexlinx , GoNet and “Pakistan Web Hosting” provide IMAP — and tell you about it.

Providers offering IMAP support are listed at . Also check out . Free IMAP: FastMail , Bluebottle and “Cwazy Mail” provide free IMAP access to email, and the storage space is 10MB. People who have Gmail accounts can download ‘Pop Goes The Gmail’ to access e-mail via IMAP.

As email is rapidly becoming an increasingly important and efficient means of communication, high-performance email access is critical. IMAP provides almost all the desirable features and should be preferred. Start using IMAP, you will find this experience simply wonderful.

The writer is a young scholar of electrical engineering at the University of Engineering & Technology, Lahore

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