Historically, spam filtering has occurred at ISPs,
on enterprise gateways (e.g., a DMZ server), on
mail servers, and on desktops. These strategies, especially when they're combined to create a multilayered
solution, have been effective in reducing the amount of
spam users receive in their mailboxes. But increases in
spam create slower mail server processing rates as well as
require additional storage for messages flagged as potential
spam. That's why many organizations are looking to replace
their first-generation spam software solutions either with
a spam-filtering appliance or by entrusting spam-filtering
tasks to a hosted service. This Buyer's Guide will help you
evaluate spam-filtering appliances and hosted services so
you can choose the technologies that provide the best email
protection for your organization.
Purchasing an Appliance
Spam appliances are standalone devices with OSs designed to
filter spam. You can deploy spam appliances at your network's
entry point or in front of your mail server. Many appliances
come with preconfigured rules, policies, and lists (e.g., blacklists, whitelists, vendors' proprietary lists) and are designed to
be ready to perform out of the box. Most appliances include
a Web-based UI that lets you centrally and remotely manage
email policies and rules, search for and release quarantined
email, and generate real-time and historical reports.
Most appliance vendors supply daily spam rules updates
to keep their appliance effective against the latest threats.
Some vendors provide this update service free for one year
when you purchase their appliance; other vendors offer their
update service on a subscription basis at additional cost. An
advantage of purchasing an appliance is that no user licenses
are required. You purchase an appliance that accommodates
the number of email users in your organization or the average
number of daily email messages your organization sends and
receives. In general, appliances offer better ROI for organizations with more than 100 users.
Using a Hosted Service
Hosted services filter email messages before they reach an
organization's email server. Using a hosted service reduces
server resource usage, requires no additional hardware or
software purchases, and means messages identified as potential spam are stored at the host site. Often, hosted service
providers can respond quickly to newer forms of spam.
Larger organizations often use hosted services to support additional email functions such as outbound filtering and encryption and adherence to compliance policies, but
hosted services are also suited for small companies with
100 employees or less or that aren't ready to hire a mail
administrator. Number of email users is usually the price
determinant in hosted services; the more email users you
have, the higher in cost the service becomes.
Many service providers make additional services available, including automatic disaster recovery and failover,
offsite message archiving (for compliance and business
continuity), data redundancy, IM protection, and outbound
filtering. The inclusion of one or more of these services can
affect the price of a hosted service plan.
Making Your Choice
The most basic requirements for antispam protection are
a comprehensive hosted service plan or an easy-to-install
appliance that guarantees high spam protection (a capture
rate of at least 97 percent) and a low false-positive rate. When
investigating hosted services, look at the uptime that the
service level agreement (SLA) guarantees and the message
latency rate. It's important that a hosted service queue messages if your network experiences downtime or a connection
fails. Also check to make sure that an appliance or hosted
service you're investigating supports your email servers, is
LDAP-compliant, and can handle multiple domains. The
more protection mechanisms—for antivirus, antispoofing,
antispyware, and antiphishing support—and filtering technologies a service or appliance supports, the better.
To effectively manage spam, mail administrators should
look for products or services that provide a Web-based interface (possibly supporting multiple languages for global users)
that lets them remotely monitor and access quarantined,
blocked, or deleted spam messages; manage policies (such
as customizing policies for different domains, user groups,
and individual users), rules, and lists; perform user-account
administration; and generate reports (some products have
dashboard displays that provide real-time statistics).
Choosing the Best Solution
The key factors you want to keep in mind are ease of use,
superior rate of filtering, scalability, pricing structure,
customer service and implementation or installation assistance, and related features or services available that might
offer valuable functionality in the future. The table on page
20 will help you compare the functionality and features of
various spam-filtering appliances and hosted services.
View Buyers Guide
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