I developed an email list manager web application (PHP w/ MySQL backend) for a client. The web application quickly evolved to support the sending of bulk emails to solicited email addresses (not spam). My client can sometimes send out some pretty large emails.
I am using the PHP Swiftmailer (with php mail() function) package to handle sending the emails. I have also set up an email queue and crontab so that the emails are gradually sent out within 24 hours. This way, the server doesn't get overloaded.
Anyways, the current server host no longer wants to support the application as she does not want to risk her server getting blacklisted (since she also has 200 other clients using that server).
My question is this: What is the best way to go about hosting this type of web application, where large emails are being sent out? I'm thinking I need a dedicated mail server, but I'm not sure how commercial hosts would feel about sending all of the bulk emails. Does anyone have any recommendations?