What is ZuckMail ?
    X-Mailer: ZuckMail [version 1.00]


I mean is this custom-made smtp mailer? or X-Mailer header with custom value like X-Mailer:myMailer ? 
What is ZuckMail ?
===

    X-Mailer: ZuckMail [version 1.00]


I mean is this custom-made smtp mailer? or X-Mailer header with custom value like X-Mailer:myMailer ? 