[Sqlgrey-users] Dealing with pooled outgoing servers

[Jeff R. <py...@fi...>]

Looking at my log today, I noticed a particular server (or set of
servers, actually) that kept connecting to retry a single message.  The
sender email, recipient email, and helo were the same but the sending
servers were different (but on the same C net).  I believe that other
ISPs use a similar technique -- AOL, for example?

Can we think about a strategy to address this, without whitelisting
these blocks?   If the C subnet is going to get whitelisted (assuming it
 has a reverse addy and is not dynamic) once it retries, is there a
fundamental reason why the C net can't be used in the connect db rather
than a full quad?

Jeff