I am creating a marketing company and am confused on one specific topic - email blacklisting. My confusion is the following:
We are going to be hosting a variety of sites. Each site will have the capability to send out email newsletters from their specified domain-name. I'm looking into a blacklist service, but my question is - since all of the hostnames come from my server IP, why would I check the sites hostname instead of just my IP? Does this make sense at all? So, in summation, my question is - do blacklist services check my IP address, or the hostname that its being sent from? How specifically do blacklists work? Also, are there any free services available?