cat /etc/pam.d/smtp                                      
auth required pam_mysql.so user=postfix passwd=uhu \       
 host=localhost \                                               
 db=postfix \                                                   
 table=mailbox \                                                
 usercolumn=username \                                          
 passwdcolumn=password \                                        
 crypt=1                                                        
                                                                
account required pam_mysql.so user=postfix passwd=uhu \    
 host=localhost \                                               
 db=postfix \                                                   
 table=mailbox \                                                
 usercolumn=username \                                          
 passwdcolumn=password \                                        
 crypt=1