We recently spent quite a long time before deciding on our filtering solution. We required a number of things that it appears the big boys do not seem to understand.  Like the biggest and simpliest we have stated time and time again. If your email solution does not offer you a method of white-listing just leave!  We have stated this many times with AOL! Comcast and now even ATT have joined the list of "LAME" ISP's who simply do not understand the importance of this simple requirement for their users.

Anyone who seeks a new provider should ask! Do you use BrightMail or GoodMail? You should ask if they can offer another alternative? These propreitary applications have some issues which ComCast has reported as a glitch, give me a break, this is simply not the problem.

Server response to MAIL FROM:

550-64.4.207.8 blocked by ldap:ou=rblmx,dc=comcast,dc=net 550 Blocked for abuse. Please send blacklist removal requests to blacklist_comcastnet@cable.comcast.com - Be sure to include your mail server IP ADDRESS.

Great Article and Frustating ISP comments about ComCast.

Have some Fun here.

The point here is simple when big companies throw large dollars at a solution without alternative methods of adjustment for their clients, they are making a serious blunder.