Increasingly large attachments can bloat your servers, clog your systems and slow user mailbox opening to a crawl, prompting help desk calls.

Worse, attachments can make messages that your users have sent bounce back, when clients set up policies to block messages larger than a certain size, say 10Mb. (In other words, a limit low enough to block a crucial marketing presentation.) Also, the bigger your email store gets, the more complicated your backup and restore jobs become. Sure, you can ask people nicely to stop sending large email attachments. But voluntary behaviour change requests usually fall flat, and besides, that solution doesn't address the client issue, says Fred Danback, CIO of Integro Insurance Brokers. Sooner or later, he says, you realise something has gotta give.

Danback ended up addressing the problem by inserting an appliance in his network to act like a big colander to catch large attachments before they reached end-users' email boxes. But it took some time to reach this decision, including attempts to get end-users to give up such large files.

"We even asked pretty please with sugar on it," says Danback, "but compliance is never voluntary."

Integro, a New York-based insurance brokerage firm founded in 2005, specialises in big clients with complex risks, and competes with the likes of Marsh and Aon. It has grown quickly, winning some 250 clients including General Electric and Unisys. Blue-chip clients making these kinds of insurance deals certainly don't want to be bothered with email hassles, Danback says.

As of 2006, Integro's email system, supporting some 400 users in five countries, was groaning under weighty attachments. "There's a lot of document transfer that takes place. We may get CAD drawings, MPEG files, technical specifications, it runs the gamut," Danback says. Not only was his internal system being taxed, but also, his users were bumping up against problems with clients receiving their messages, since many firms limit attachment sizes, to prevent problems like denial-of-service attacks, Danback says.

"Then you get the help desk call," he says. "You had to find ways around it, but it was inconvenient." Also, there's the issue of people taking matters into their own hands.

"When you have successful people, they'll find a way to be successful," he says. For Danback, this meant some users were resorting to using Google's Gmail on both sides of the email exchange, in order to avoid client email system restrictions. "That's insecure, and it's not effective," Danback says. It's also widespread. In a recent Osterman Research study of midsize and large enterprises, 60% of people report they use personal email accounts to do business when the corporate system doesn't work, and 17% of people report they use these accounts for business every day.

Danback decided to address his company's problem in early 2007 by installing an email attachment appliance from Accellion.

Still an emerging category of technology products, but growing, email appliances (sometimes called caching appliances or secure file transfer appliances) shift the email messages with huge attachments away from your email server, and into the appliance for storage. Plugging right into the network like many other appliances, these boxes address the problems with the email recipient systems too. Danback has set up the appliance so that when anyone in his firm sends a message bigger than 10Mb, it kicks over automatically from his Exchange server to be routed via the Accellion appliance.

When the recipient gets the email message, he doesn't get the attachment inside the message but instead clicks on a Web link to grab the document. The user can save the document to his machine's hard drive. At Integro, Danback typically sets those links to live only for 30 days. (You can adjust this time period depending on your wishes.)

Accellion boxes configured similarly to the one Danback uses cost between $5,000 and $10,000. Other vendors competing in this space include GlobalScape and Intradyn; offerings include traditional software and appliances. The products often blend some email security, archiving and attachment management chores.

Of course, the old-fashioned alternative to an appliance like the one Danback set up is asking users to utilise a regular FTP server for large email messages. But he rejected that option, since it would mean asking users to futz with something other than their usual email client, which is in itself a barrier, Danback says. With the Accellion appliance, the user sends any message in the normal manner. Besides, Danback says, the appliance proves simple to set up and maintain.

"It's just easy. It's self-contained. It simplifies our infrastructure," Danback says.

Danback's business users like it for another reason. Because their insurance industry competitors are dealing with the same large documents and email woes, anything Integro brokers can do to make their interactions with clients more seamless can only help them win business, Danback says. "We had to find a way to differentiate ourselves from our competitors," he says.

The more attachment-heavy your company is, the more a caching appliance makes sense in terms of ROI. If you have complex discovery and compliance needs, you will want to consider using an appliance in concert with email archival software. Both of these product categories are growing, with good reason: Another recent Osterman Research study found that 59% of enterprises call messaging storage growth a serious problem. And messaging storage needs are growing at a clip of about 35% per year, according to Michael Osterman, principal of Osterman Research.

What's Danback's advice to other CIOs about email appliances? "Look at what could go wrong with your email and do something about it now. So you don't get yourself in a situation where you have proprietary or secret information in the public mail," he says.

Also, he says, be choosy about the number of non-Microsoft products you add to your Exchange/Outlook environment. "The more features you add that are not Microsoft, the more chance you can create disruption," he says, noting that one reason he likes the Accellion box is he's had no issues other than initial setup tweaks during testing.

Eventually, Danback says, he envisions Microsoft itself buying a company like Accellion and bundling such functionality into packages for enterprise customers. "It just makes a whole lot of sense," he says.

Until then, he's sticking with his ticket out of attachment hell.