Server-Side Antispam Solutions
For enterprises and ISPs, the client-side filter does nothing to relieve the network traffic or reduce the resources needed to process e-mail. To positively impact a company's infrastructure costs, an antispam solution needs to stop spam before it enters the enterprise. This section looks at various types of solutions to help do this.
Block List Companies29
A block list is a list used to indicate e-mail addresses or domains from which you want to block e-mail. Companies have used their own lists for years to help determine which e-mails are spam. Block list companies such as Brightmail, Spews.com, and SpamCop make the process more efficient by combining lists from multiple companies. This is one of the easiest ways for companies to protect themselves from unwanted e-mails. The savings made from not having to process spam can easily compensate for the fee charged by these companies.
Antispam Server Software
Some companies sell software that is run on a server between the Internet and the company's e-mail server. The purpose of this software is to remove the burden of filtering e-mail from the e-mail server. This type of software can relieve companies of the expense of having to create and manage their own solution. In an effort to benefit from their investment in antispam software, for example, Boeing is commercializing its internal solution, which it is calling MessageGate Security Edition.30
IronPort not only creates systems to permit companies to send bulk e-mail, they also sell servers that enable companies to filter spam.
In addition, two solutionsSpam Sleuth and SpamSquelchertake a slightly different approach to the way that they protect companies from spam.
Enterprise from Blue Squirrel provides a solution that blocks spam from reaching a company's e-mail server. This product enables administrators to configure the many filtering options while enabling users to personalize their settings through a client application. The following list identifies some of the product's many features:
Works with any e-mail server
Challenge-response to force senders to validate their e-mail at a Web site
Permits domain-level rejection or acceptance lists
Replies to spam transmissions as undeliverable
Validates senders by using the following criteria:
Checks for missing reply address
Validates that from address is equivalent to reply address
Compares the IP and DNS data against rejection lists
Checks subject and body text against blocked words
The product SpamSquelcher is marketed by ePrivacy Group. This product is unique in that it does not block any e-mails from reaching your company. What it does is increase the processing time for delivering spam for companies sending spam. In this manner, legitimate e-mail is not accidentally lost because of an overly sensitive filter. Decreasing the delivery bandwidth for spam has the effect of increasing the bandwidth for legitimate e-mail while increasing the costs of spammers who send e-mail to companies that deploy this technology.