Please read the following PDF paper (Chrobok, et al) for an explanation, details, and reason for implementation of a pull-based email delivery architecture:
http://www.cs.otago.ac.nz/homepages/andrew/papers/2009-12.pdf
Please read the following PDF paper (Chrobok, et al) for an explanation, details, and reason for implementation of a pull-based email delivery architecture:
http://www.cs.otago.ac.nz/homepages/andrew/papers/2009-12.pdf