For the past 20 years or so Military Messaging has been based around the X.400 messaging standard. NATO produced a set of extensions to X.400, and published these as NATO STANAG 4406 (the formal nature of X.400 and its support for delivery notifications suited the high availability requirements demanded by Military Messaging systems). However, in the commercial world the X.400 standard is rarely used, preferring instead to the use the Simple Mail Transfer Protocol (SMTP) standard for submitting business and personal email (why X.400 wasn’t adopted is a topic of many discussions, but complexity and cost seem to be the main drivers for preferring SMTP). Traditionally, the Military Messaging world tends to follow what is happening in the commercial world, and the recent publication of the IETF RFC6477 standard is the one step towards Military Messaging adopting the SMTP standard.
Microsoft Exchange is undoubtedly one the leading messaging solutions in the world and with the use of Microsoft Office (365) at home it means we only have to learn one system for both work and home use.
With Military Messaging adopting the SMTP standard this becomes easier; no more complicated X.400 O/R addresses to contend with (although I’m sure older legacy X.400 systems will stay around for a while), making Microsoft Exchange a more attractive platform than before. Handling ASN.1 encoding errors or routing problems with X.400 messages is always a headache for system administrators, requiring specialist knowledge to track down problems (although hopefully most of these issues have been resolved by now).
The release of SAFEmail® v3.8 enables military and Homeland Security organisations across the world to communicate securely using SMTP, as well as X.400 protocols, using a single desktop application, Microsoft Outlook.
Security in Military Messaging is also defined by NATO STANAG 4406, which is actually based on the S/MIME security standards defined in the commercial world. By Military Messaging adopting SMTP this means the same S/MIME standards can be used, albeit protecting MIME content rather than the X.400 content.
It seems Military Messaging has been destined to use SMTP all along.