Applied Research Of Qmail-based Large-scale Email System (JNUqmail)

Firstly This paper introduces some principals of email, and describes some protocols of email system, such as SMTP, POP3 and IMAP. Then it discusses the principals , concepts and application of LDAP(Lightweight Directory Access Protocol).Due to some deficiency of sendmail, which can not fulfill our current needs, we must find an alternative, qmail is a new kind of MTA, which design email system by module. And it can provide functions we need. So I adopt qmail as MTA, and then I review some principals and flowchart of qmail.RFC821, 2821,2554, 2822,2920,3030 have defined the Protocol SMTP. I use self-programming method, which is the certification RFC2554 supplied, to transmit emails by LDAP in qmail system. I store username and password in LDAP, which can speed up the access. And I adopt Kerberos, which guarantee the access of LDAP. Meanwhile, using LDAP also can provide SMTP authentication, which can avoid sending mail from our email system by false name.With the increase of information in college, it becomes necessary to communication between each other in email system. This paper introduces the development of college-oriented object class, and give some suggestions to the application of object class of email system in college.With the development of mobile technology, SMS(short message send) has become popular. It is being popular using mobile terminal sending and receiving email. To fulfill large-scale access, this paper discuss the application of J2EE in email system.