Mailster offers by default three delivery methods:
Additionally you can add more methods with plugins
This is the default method and is not recommended for bulk mailing in general. Often providers limit the amount of mails which can be sent with this method to prevent spammers. Talk to your host about the limits and if you are allowed to send bulk mails. Problems?
This is the method you should use if you have many subscribers. Contact your host for the credentials. SMTP requires certain ports to be open. Problems?
Googles email service can be used. Technically it’s the same as SMTP but you only have to enter your Gmail credentials.