I have after 2 weeks of work(so I am not very clever) a Postfix server . Thank you for your tutorials and I want to thank especialy to FALKO. How can I have default users who cannot send external mails and how to set in main.cf users who have this rights? Who can help me?I migrate from qmail cause I didn't succed there to make that diffrence to posfix wich I belive have more stuff built in... I read and I tryed from :http://www.postfix.org/RESTRICTION_CLASS_README.html to understand how to Restricting what users can send mail to off-site destinations BUT I am NOT too clever so ... Thank you for those who will give me attention.