The war on spam wears on and a question from one of our users sparked this blog post. "What makes your spam filtering so dam great"?
Many hosts install spam assassin perhaps a bit of clam-av virus filtering and call it done. Maybe they enable grey-listing and then brag about the service level.
Now comes, the end user who understands almost nothing about any of this. They accept the market hype and take it as the gospel. They want to know nothing, they just do not want the spam filling up their in boxes. They feel this is something which should just happen. Which is why many hosts & ISP's just install spam assassin and say you have e-mail filtering.
Yet other hosts & ISP's have this idea that just buying a Barracuda Firewall is the answer. After all someone told them Barracuda makes the best mail filtering device available. So booyah they are an instant expert. The success of the Barracuda firewall product, and the continual increase in spam are probably the reasons for an increase in email backscatter. Sadly, too many Barracuda Spam Firewall customers still enable auto-replies for spams that get blocked. This is not necessarily the fault of Barracuda firewall, but more of the administrators do not understand the impact of their actions.
Most people send a limited number of messages to people who they have a relationship with. Spammers however send millions of messages to people who they have no relationship with. A real email message will keep retrying if the server isn't ready and will generally play by they rules. Spammers will try to circumvent the rules to try to deliver as many messages to as many people as possible. They try the back door before they try the front door and if the back door rejects them they move on. This is why grey-listing is important and blocks much of this behavior since most spam is not sent out using RFC compliant MTAs; the spamming software will not try again later.
While grey-listing is important, it like spam assassin can only answer part of the mail filtering scheme. Understand that the war on spam is waged against people who make their living off making it to your in-box. This typically makes no standard canned code or device on its own merit enough to prevent the well armed spammer from be successful.
To make matters worse many desktops around the world are nothing more than the instruments of spammers with mal-ware being inserted turning their machines into zombies, Sophos estimates half a million zombie PCs are operating worldwide. Given this conservative estimate of the volume of these zombie machines, it only seems logical that a desktop user cannot continue to assume that these things are all on the administrators who handle their mail.
The point of the article is why our mail filtering is better than other providers. Our intent is to offer a truly flexible efficient package, which supports features like MailScanner Spam Assassin, Razor, DCC, Pyzor, Grey-listing and Dynamic Bayesian indexing from our pool. We believe that putting as many features as possible directly in the hands of the domain email administrator is the right approach to take and we stand by that.
While we are focused on the windows platform for our mail servers due to the fact that SmarterMail is one of the best email server packages available. We also understand that Linux servers are currently better suited to the tools available for mail filtering. We work day and night to provide the best mix, while capitalizing on the strengths of each and ignoring any weakness each platform might have. Our email filtering is performed by collection of clustered servers with a single purpose, filtering the unwanted email while still allowing the valid email to quickly transit the MTA.