Stop Spam protection guide - Email Security for Businesses
There are a few options in the way you can choose to stop spam mail. This would depend on what scale you would want to block spam, as explained below;
If you want to stop spam mail on one or a few machines, then just a single machine spam blocker would be suitable, take a look at my spam software guide. An ideal product would be to purchase an all in one package stopping spam alongside viruses, spyware and adware.
If you are a business with 15 or more users (E-mail accounts) you have two options to stop spam mail;
Option 1 – You can purchase a dedicated spam blocker which would sit on the edge of your network filtering spam from your legitimate e-mail. The spam filter would only send on legitimate mail and either quarantine or drop spam.
Option 2 – Or you can pay for this to be done via a third party managed e-mail security provider. They would filter all your bad e-mail (spam) and send you only your good (legitimate) e-mail. Using a third party company means they will deal with monitoring, maintaining, managing and being responsible for your company's spam security. Their main objective would be to stop spam mail destined to your company, and would only forward your company legitimate mail.
How hosted E-Mail Security works
The above diagram shows how a managed e-mail security provider would stop spam mail destined for your business. When you sign up with an E-mail security provider you would ask your ISP (internet service provider) to point your MX (mail exchanger) record to an IP address which would be the address of your e-mail security filter. e-mails destined for your company would then be sent to your new hosted e-mail security provider’s spam mail filtering system. Their systems would filter your good e-mail from your bad e-mail and either drop or quarantine your bad e-mail and in turn send your legitimate e-mail to your exchange server, which would then deliver your e-mail to your end user’s e-mail clients (typically Microsoft Outlook, Outlook Express).
Option 1 is suitable if you have someone who is trained, and can manage and maintain the product filtering your E-mail. Option 2 is ideal if you do not have the resources in house with the required technical skills to manage and maintain an e-mail security product to stop spam mail for your business.
If you are a business hosting your own exchange server you can purchase spam protection from a managed hosted service. There are many companies providing such a a service such as Websense, Symantec, Google, Mcafee and more. As a matter of fact today it is more common companies are looking for protection as a hosted service.
Wikipedia's guide to Anti Spam Techniques