Unless you are sending the bulk emails from a country that is not compliant with the CAN-SPAM Act, sending all bulk email messages at once is very likely to cause you trouble, as your email provider will catch all emails and suspend your account. Even if these emails pass the filters of your own mail server provider, they will likely get your email address black-listed on anti-spam servers, due to the high frequency of outgoing bulk emails.
As a result, if you plan to send hundreds or thousands of bulk emails, it is essential not to send them in a single session. Use a bulk email software capable of scheduling bulk emails, like AB Bulk Mailer. With AB Bulk Mailer, you can opt to send only a few emails at a time, scheduling sessions at pre-defined periods. For example, you can choose to send one email in (personalized), 98 mails with a bulk option. The software does not have any inbuilt smtp server.
Using AB Bulk Mailer you can send personalized emails to a specific group of people. You can provide unsubscribe options to the people, so that they can unsubscribe from you. Please unsubscribe people immediately once you receive the request for the same. You can manage the bounced emails and track mailing history.