“E-mail is down.”

Even writing those words causes a visceral feeling of imminent doom.

There’s no question that e-mail has become of strategic importance in all aspects of business.

In a sense, it has turned out to be the digital equivalent of the “Girl Friday.” Digital conversations are recorded and tracked. Appointments are confirmed and received. Even deals are made and broken over e-mail.

I think it’s fair to say that e-mail has become the heart of most businesses, pushing, pulling, and cajoling information from around the country or throughout the world (for those companies with global operations).

In looking at the numbers in my own company, The Hoffman Agency, we send out around 57,000 e-mails per month, with incoming e-mails hitting around 45,000 within that same monthly cycle. It reminds me of that scene in the movie, “Crocodile Dundee,” when Paul Hogan pulls out a massive knife and states the obvious, “This is a knife.” Well, that’s a ton of e-mail for a company with 120 employees.

Of course, it’s not only the quantity of e-mails, but also the fact that the application falls under the mission-critical umbrella that causes heartburn for IT folks. In our case, with offices in the U.S., Asia, and Europe (combined with employees burning the midnight oil), the e-mail server is running literally 24x7 throughout the year.

This brings me to the crux of the issue: how to improve the uptime of an e-mail system. If you’re looking to truly bulletproof your system -- that calls for redundancy.

Let’s start with security

At the foundation level, I recommend Microsoft Exchange Server, which gives you control over what comes in and goes out. Without getting into the technical details, the product verifies the credentials of each person logging on and off, and that keeps the bad guys out.

It’s not cheap. Figure on spending at least $18,000 between labor costs, hardware, and the software licenses to get Microsoft Exchange Server up-and-running for 100 users. The software license does scale down with pricing available for as few as five users.

I recognize that there are a fair number of small and mid-size businesses depending on Post Office Protocol (POP) for their e-mail operation.

While you can’t beat the price (i.e., free), the POP approach puts you at the mercy of your Internet service provider for security, which can be hit or miss. Plus, POP e-mail is stored on the local PC instead of on a central e-mail server. This means anyone in your company using a PDA, smartphone, BlackBerry, or the like essentially opens a door to your IT operation that you have no way of watching.

And then there's spam

Of course, I can’t overlook that wonderful mass blast that brings enlightenment to our children’s vocabulary, known as spam. There are three approaches to stopping spam: on-site spam filters (typically installed on the e-mail server), client side filters (installed on the individual machine), and managed spam filter services.

We’ve used both on-site spam filters and client side filters. I’m not a fan of either. Both approaches can be administrative-intensive. I saw a quote from Osterman Research last year stating that more than 50 percent of the cost in managing an e-mail system is in labor. I believe it.

That’s why we turned to deploying a managed spam filter service in which our e-mail goes through a third-party for “cleansing” before heading to our staff’s computers. In our case, we use a firm called eDoxs (costs around $2.60 per mailbox per month), but there are other reputable firms out there, such as Emerald, and LastSpam. To give you a sense of the problem, eDoxs blocked 1,062,876 e-mails last month (not that we’re counting).

Another point on spam: If you allow employees to make online purchases on the company computer, ask them to use a personal e-mail address from Yahoo!, Gmail, etc. We had an employee leave over six months ago, and I’m still cleaning up e-mails that can be traced to her purchase of a pair of shoes online.

Stay on top of disk space

Beyond staying on top of security, I recommend a constant monitoring of disk space. Running out of disk space is one of the most common points of failure in an e-mail system. Given that the price of disk storage has dropped so low, there’s no reason to max out disk utilization before adding more space.

On the topic of storage, sending large files as e-mail attachments can also grind your e-mail system to a crawl. This issue has become more pronounced over the past couple of years as people dispatch digital photos from the kid’s birthday party via company e-mail. At the very least, consider putting a file limit on attachments.

A second approach is to look to a new category of services that specialize in moving large files from point A to point B without depending on your e-mail roadways. These services go by clever names such as Sendthisfile.com, Yousendit.com, Box.net, and Dropsend.com, allowing you to upload the file to their websites by filling out a form. Once the file has been uploaded, the service shoots an e-mail to the recipient with the link to the file. Most of the basic packages come free with a modest cost added depending on variables such as number of files, size of the files, and number of downloads.

When the laptops go home

As more companies move to laptop computers, it’s natural that these same machines pull double-duty for personal use, even extending to family members. Guide your employees that if they’re going to allow Johnny to surf the net on the company laptop to complete his report on the history of Macedonia, they need to exit out of e-mail. As elementary as it sounds, this is another cause of “undesirables” entering the company e-mail system.

These suggestions give you a fighting chance to keep the e-mail running on time.

Linda Wilson is the IT director of The Hoffman Agency, a global public relations firm with 120 employees.