http://forum.oissite.com/18/ShowForum.aspxenCommunityServer 2.1 SP3 (Build: 20423.1)http://forum.oissite.com/thread/21.aspxThu, 02 Nov 2006 00:00:11 GMT491632c6-5f62-4df2-ab15-8dbf58ea1f8c:21souhil0http://forum.oissite.com/thread/21.aspxhttp://forum.oissite.com/commentrss.aspx?SectionID=18&PostID=21<P><STRONG>Recently Yahoo has started "greylisting" almost every email that goes through their mail server.</STRONG> </P> <P>Greylisting is a way of attempting to block SPAM. Yahoo mail denies the first delivery attempt of an email (<I><B>451 Message temporarily deferred - 4.16.50</B></I>). They assume that SPAMers don't try sending the same email twice, so they put the ip address of that email server on a list and then if the delivery is retried within a short amount of time, they assume that it is a good email. </P> <P>Yahoo mail denies the first delivery attempt of an email (451 Message temporarily deferred - 4.16.50). They assume that SPAMers don't try sending the same email twice, so they put the ip address of that email server on a list and then if the delivery is retried within a short amount of time, they assume that it is a good email.<BR><BR>So we believe in next retry it should deliver your message.</P>