There are five fundamental ways to block spam. Which you choose will depend upon your organization’s architecture and business needs.
1. On the desktop. Many of the anti-virus vendors have spam blockers that integrate with Outlook, Eudora, etc. e-mail clients. This is one of two options available for home users. Pros: quarantine is local to your system, and you don’t have to depend on enterprise configurations. Cons: consumes resources on your PC, doesn’t scale for enterprises.
2. On the e-mail server. Many spam-blocking programs are available that run right on your Exchange or Notes server. Pros: installs on your e-mail server – no additional servers needed. Cons: all the spam still hits your e-mail server.
3. A spam-blocking appliance. These appliances terminated your inbound e-mail connections and filter out the spam, so that only clean e-mail reaches the e-mail server. Pros: shields your e-mail server from spam, freeing up cycles and disk space. Cons: another appliance to maintain.
4. Spam blocking service. Your e-mail is directed to the service, which filters the spam, and forwards to your e-mail server only clean e-mail. Pros: spam never touches your network, freeing up network bandwidth. Cons: physically located elsewhere.
5. Filtered by your e-mail provider. The large providers such as Yahoo, Gmail, AOL, and others filter spam so that only clean e-mail reaches your inbox. This is the other option available for home users. Pros: done for you automatically.
All of the above solutions can provide a “quarantine” whereby users can examine blocked messages, in the event they are missing some inbound messages that may have been blocked.
Read more in Blocking Spam and Spyware For Dummies