On Sun, 2010-06-27 at 08:24 +0800, Ed Greshko wrote: > A well written greylisting milter will utilize a database to maintain a > list of sending MTAs that have retried. Of course. However, many large sites (including ours, which is only medium sized) have multiple IP addresses that send out mail, which results in the same sender getting greylisted multiple times. > Additionally, the good milters > will have the ability to specify whitelists and blacklists. Specifying them is one thing, maintaining them is another. Static blacklists are useless for the reasons already stated (the sending IP addresses of the spammers change too rapidly). White lists could be (and are) used, but until someone actually has a problem, you can't know what has to be whitelisted. In the several years we have been using greylisting, only once have I actually had to whitelist a sender (because it was some graduate student in Italy using a homegrown mail sender that didn't have retry capability; the scientist here is not interested in hearing about how the sender is violating several RFCs )-: At any rate, the point is that greylisting *does* cause *some* delays. I am NOT saying it shouldn't be used, in fact quite the opposite. I *am* saying that someone looking to implement greylisting should be aware that it will cause some legitimate mail to be delayed. --Greg -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
