View source for KB 437

===Why can't you guys just filter out the spam!===
  Article ID: 437
  Created: Aug-30-2006
====Question or Symptoms====
 
    It's easy to recognize, what's the big deal?
 
====Resolution====
 
    1. Humans pattern match really well.
    Here are two examples to think about in how you'd tell a computer to
    recognize them:
    -------------------------------------------------------------------------
 
    Aoccdrnig to a rscheearch at an Elingsh uinervtisy, it deosn't mttaer in
    waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht frist
    and lsat ltteer is at the rghit pclae. The rset can be a toatl mses and
    you can sitll raed it wouthit porbelm. Tihs is bcuseae we do not raed ervey
    lteter by it slef but the wrod as a wlohe.
 
    ------------------------------------------------------------------------
    \/1agr@
 
    V`agra    V1agra    V iagra    v`aGra    `/1agra vi@gr@    v i a g r a
    vi agra    via gra    vi ag ra    V1 @g ra    V.I.A.G.R.A.
                 __   __
    \\ //'  /\ | _+ |__| /\
     \/  | /--\|__| | \ /--\
 
     And these are just using plain ASCII text.
    ------------------------------------------------------------------------
    2. The spammers use the same tools we use to fight spam as test beds
       to craft spam. They have the same Bayesian filters, the same Spam
       Assassin pattern lists, the same virus signature databases and are
       updated in the same timely manner of new methods to catch spam.
       The difference is it's often their full time job to craft spam that
       can get through the current technology's filters, where as the folks
       fighting spam have fewer resources.
 
    ------------------------------------------------------------------------
    3. We have to deliver ALL your desired mail, NONE of the spam, AND
       we have to do it in a timely fashion. Here are some ways a message
       can be delayed.
 
         Did it get caught in the queue of one of our front end spam filtering
         appliances?
 
         Was it stuck behind hundreds of thousands of bounced messages sent
         offsite with a legal SWCP/NMIA/Thuntek email address as its reply-to?
 
         Was the mail server under a dictionary attack of an army of zombies
         controlled by a spammer trolling for valid email addresses?
 
         Were our anti-virus machines hobbled by a carefully crafted poison
         pattern embedded in a virus?
 
    This certainly doesn't mean we're surrendering in this war against spam!
    We're constantly trolling for new ways to filter without throwing out
    the good stuff. About every six months we beef up our email system by
    buying new machines and/or re-engineering our email systems.
     It's an unending war but we're committed to trying to deliver all your 
    desired email fast and spam free.