A Secure Sendmail Based DMZ for the Corporate Email Environment

Adding a layer of simple mail transfer protocol (SMTP) infrastructure in the demilitarized zone (DMZ) between the Internet and your corporate email system is an effective way for corporate environments to enhance the security and functionality of their electronic email systems. We will explore the concept of using the sendmail SMTP application as a DMZ for the corporate email system (i.e. Exchange, GroupWise, Notes, etc). This concept has a number of benefits, including increased security, scalability, stability, and flexibility. This approach will probably only be attractive to larger environments as smaller organizations will have a hard time cost justifying the extra server(s) required and supporting the added complexity. This approach should work equally as well with other SMTP systems such as Qmail, or Postfix that are appropriately secured.