Isode Ltd SMHS Ltd SMHS Ltd A Military Message Handling System (MMHS) processes formal messages ensuring release, distribution, security, and timely delivery across national and international strategic and tactical networks. The MMHS Elements of Service have been defined as a set of extensions to the ITU-T X.400 (1992) international standards and are specified in STANAG 4406 Edition 2 or ACP 123. This document specifies how a messaging service that meets these service definitions can be provided using the SMTP family of protocols. It defines a profile that can be used by those wishing to ensure that these services are provided.