Facilitating secure mail in a high assurance LAN

Abstract

Currently, almost all DoD systems are operated at a single level, classified or unclassified. The problems encountered on these single level systems with mail exchange, its storage, and manipulation are the multiple networks and workstations required to handle different security levels of data as well as the high cost of maintaining them. The Naval Postgraduate School Multilevel Secure Local Area Network (MLS LAN) project supports a high assurance server. This LAN is COTS-driven (commercial-off-the-shelf) and enforces a mandatory security policy while permitting users to employ standard office productivity tools on standard workstations. Initially, there was no means for multilevel mail exchange between clients of the system. This research was to implement the simple mail transfer protocol (SMTP) server, Sendmail, on the Wang Federal XTS 300 as a multilevel server. A port of a UNIX version of Sendmail 8. 9.3 was made to the XTS 300. Modifications to Sendmail were required so that it could be supported by the UNIX-like XTS 300 STOP 4.4.2 operating system Sendmail proved to be a successful mail server for exchange of mail between system clients. Tests demonstrated successful transmission of simple mail and mail with attachments.