title: Postfix sending mail from nonexistent email addresses
body: <p>I recently migrated from Courier to Dovecot. The main guide I followed for configuring Postfix + MySQL + Dovecot was this one: <a href="https://library.linode.com/email/postfix/postfix2.9.6-dovecot2.0.19-mysql" rel="nofollow">https://library.linode.com/email/postfix/postfix2.9.6-dovecot2.0.19-mysql</a></p>
  
  <p>Everything works perfect, but when I change the mail address in the mail client, leaving the correct login and password for the servers, and send an email with that fake mail (and domain) address, Postfix just sends it, without verifying if that email address existed in the database and without verifying if that email address was even mine.</p>
  
  <p>So, there must be something wrong with my SMTP configuration. 
  This is my actual configuration:</p>
  
  <pre><code># Requirements for the sender details
  smtpd_reject_unlisted_sender = yes
  smtpd_reject_unlisted_recipient = yes
  
  smtpd_sender_restrictions =
          warn_if_reject,
          permit_mynetworks,
          permit_sasl_authenticated,
          reject_non_fqdn_sender,
          reject_unknown_sender_domain,
          reject_unauth_pipelining,
          reject_unlisted_sender,
          reject_unverified_sender,
          permit
  
  # Requirements for the connecting server
  smtpd_client_restrictions =
          reject_rbl_client zen.spamhaus.org,
          reject_rbl_client blackholes.easynet.nl,
          reject_rbl_client bl.spamcop.net,
          permit
  
  # Requirement for the recipient address
  smtpd_recipient_restrictions =
          permit_mynetworks,
          permit_sasl_authenticated,
          reject_unauth_pipelining,
          reject_non_fqdn_recipient,
          reject_unknown_recipient_domain,
          reject_unauth_destination,
          reject_unlisted_recipient,
          reject_unverified_recipient,
          check_policy_service inet:127.0.0.1:10023,
          permit
  
  smtpd_data_restrictions =
          reject_unauth_pipelining
  
  # require proper helo at connections
  smtpd_helo_required = yes
  # waste spammers time before rejecting them
  smtpd_delay_reject = yes
  isable_vrfy_command = yes
  </code></pre>
  
  <p>Anyone?</p>