My recent decision to look for an ISP that supports IMAP4 e-mail touched a nerve among readers. Readers arguing against IMAP4 claimed ISPs will not tolerate the kind of server storage that IMAP requires.
Maybe so, but I wonder if this is a "glass is half-empty" view of the problem. Some ISPs may see IMAP4 as a business opportunity. They could add automatic spam filtering (which would keep storage requirements down and attract customers) and charge for the extra storage.
Other readers pointed out that IMAP4 isn't necessary because POP3 already allows you to keep your mail on the server. True, but IMAP4 also lets you manage your mail at the server. With a good IMAP4 server, all of the client mail handling you now do locally - managing folders and moving mail between them, filtering messages, and so on - is done at the server. And you're not bound to the server.
A good IMAP4 client will let you read and respond to messages off-line when you need to.
The most intriguing suggestion came from a few readers who knew from past columns that I'm using a Linux box as my Internet gateway. They suggested that I could put up my own IMAP4 server on this box and use a utility called fetchmail to pull down mail from all of my POP3 accounts. This piqued my interest because, in this scenario, I get the benefits of IMAP4 without having to change my ISP or existing e-mail accounts.
So I tried it. It not only works, it works so well I realised that by focusing on the IMAP4 at the ISP, I was ignoring an elegant solution for any IS department that has to support a large number of users who need access to their company e-mail while travelling.
Consider the storage issue. An ISP is only responsible for the mail that resides at the server. An IS department is responsible for the mail at the server and at every client, including multiple clients per user.
Even with all the nagging IS managers do to get users to trim their inboxes, it's not unusual for those users to have hundreds or even thousands of the same messages and attachments on their desktop, notebook and server.
Worse, when these users do not have the same messages on every client, it's usually for the wrong reason. Most e-mail products are like a box of chocolates. No matter which box you open (desktop, notebook, a co-worker's notebook when yours breaks), you never know what you're going to get.
Of all the products I have used, only Lotus Notes keeps all my clients synchronised well. But the synchronisation process can be tedious and I can't search archives on my notebook.
Notes also has among the worst of all storage requirements. An empty, unindexed Notes mailbox file starts at 2MB, and doesn't even begin to measure the space the client software itself consumes.
As wonderful as it has been working for me, I can also see that IMAP4 is not a magic bullet. IMAP4 is an evolving protocol that is only now beginning to come into maturity, so people are interpreting even the same revision of the standards differently. I have tried a half-dozen clients that claim to be IMAP4 compliant, and a couple have compatibility problems with my server (or the other way around).
Another thing. Security risks aren't unique to IMAP4, but if you make a corporate e-mail system available to your users via the Internet, you risk opening your network to attack. If this is your first attempt at granting Internet access to corporate e-mail, find and plug the leaks before you go online.
The Web site www.imap.org/products.html is a great launching point to find a good list of commercial, shareware and freeware mail client and server products, many of which support various revisions of IMAP. I used Red Hat Linux 5.0 (www.redhat.com) with the Cyrus server (andrew2. andrew.cmu.edu/cyrus/imapd).
If you have a lot of people on staff who travel, would you go with an IMAP4 server as a corporate solution for e-mail?