123 Hidden Sender sends absolute ANONYMOUS bulk emails. You won't lose your ISP service. It is trouble free! Your IP address will not be shown in the E-Mail-Adresse headers! All you do is input your message, subject, and E-Mail-Adresse addresses, and then 123 Hidden Sender does all the rest. No relays to deal with anymore. No need for expensive bulk ISPs. Port 25 is not a problem.