We plan to create a bulk marketing marking site like getresponse , mailchimp etc., We need to know what are the server requirement for that site ? What is email whitelisting or ip whitelisting ?
for something on that scale you should be looking at least the following. 2 or 4 x QuadCore XEON 2.0Ghz or higher 16 GB RAM Mirrored RAID for HDD redundency and at least 10mbit UNMETERED connection. You will also need to look at getting multiple IP blocks and getting them white listed on the large ESPs