M-Switch is a high-performance, robust and highly flexible messaging server which can be configured to act as an SMTP or X.400 message transfer agent. M-Switch can also be configured as a gateway between a number of different high-grade/formal messaging protocols widely used in military communications.

This page looks at functional capabilities specific to military messaging protocols however it should be noted that, as this gateway is based on the core M-Switch product, it also supports conversion between the standards discussed on this page and all of the other email messaging standards supported by M-Switch, including SMTP and standard X.400 as discussed on the M-Switch MIXER Gateway product page.

In the sections below we look at the different military messaging protocols supported by M-Switch in a gateway configuration:

It is important to note that M-Switch can be flexibly configured to handle multiple "any-to-any" message conversion channels in a single gateway.

ACP127 Military Messaging

ACP127 is a widely deployed military messaging standard with its roots in Teletype systems. ACP127 is used for strategic messaging and over HF Radio, as well as being used in BRASS (Broadcast & Ship to Shore) systems. M-Switch can be configured to provide Gateway support between ACP127 (as well as the US variant DOI 103S), STANAG 4406 and Military Messaging over SMTP. It can also be configured as an ACP127 relay, routing between ACP127 peers.

M-Switch supports ACP127 connections over TCP and HF Radio (using STANAG 5066), with support for Serial Line connections currently under development. Unlike other M-Switch configurations, there is no client support for ACP127 in M-Switch. Clients, such as Isode's own Harrier, can connect via an MTA supporting Military Messaging over SMTP.

Detailed information can be found on the M-Switch ACP127 product page.

Military Messaging over SMTP

M-Switch supports SMTP extensions for military messaging as described in the whitepaper [Military Messaging (MMHS) over SMTP], and in particular RFC 6477 and RFC 7444.

Isode has been at the forefront of developing standards for military messaging over SMTP as an alternative/complement to existing specialised formal military messaging standards such as ACP127 and STANAG 4406. With Military Messaging over SMTP, widely available SMTP infrastructure can be shared between military and informal email, reducing management overheads and supporting communities where only a partial military messaging capability may be required, or where a small subset of users require that capability.

Please contact us if you want to evaluate M-Switch configured for military messaging environment.

STANAG 4406 Military Messaging

STANAG 4406 is the NATO standard for Military Messaging based on X.400. STANAG 4406 defines a number of functional and security features to support formal military messaging.

M-Switch can be deployed as a STANAG 4406 Military Message Transfer Agent (MMTA) over internet quality links, as a Lightweight Message Transfer Agent (LMTA) supporting STANAG 4406 Annex E in a constrained network environment, as a Tactical Interface Agent (TIA) for switching messages between MMTAs and LMTAs and as a gateway between STANAG 4406/E and other supported messaging protocols.

For more information on STANAG 4406 please see the solution page on STANAG 4406 Military Messaging. For more information on gateways between standard and constrained networking environments please see the page on Constrained Network Gateways.

ACP145 Gateway Support

ACP145 is a specification from the CCEB (Combined Communications Electronics Board) defining how military messages are exchanged between nations without constraining the approach taken by those nations on their national military networks.

As an ACP145 Gateway, M-Switch can connect to national networks and generate and verify ACP145 compliant content. The key capabilities include message signing of outbound messages, message signature verification & stripping of inbound messages, adding an ACP145 compliant security label to outbound messages (often derived from a national label using security label mapping) and security label mapping for inbound messages.

ACP145 requires an ACP133 directory to provide address book services to peer nations, Isode ACP133 compliant M-Vault directory can be used for this purpose.

For more information on ACP145 see the Isode whitepaper [ACP145: Isode Support of International MMHS Gateways]. Please contact us if you want to evaluate M-Switch as an MTA or Gateway in a military messaging environment.


Configuration and Operational Management of M-Switch Gateways can be performed using the MConsole GUI, Isode central tool for messaging management.

Configuration Management

MConsole allows for full GUI configuration of MTA and Gateway configurations. Multiple messaging/gateway configurations can be managed, all of which are stored in a directory (usually Isode's M-Vault). The screenshot below shows MConsole management of an ACP127 capability.

Operational Management

Isode provides a number of management tools and capabilities with its products, to enable control and monitoring of an military messaging system. MTAs and Gateways can be monitored using SNMP (Simple Network Management Protocol), which is ideal for monitoring large numbers of servers, and supported by Industry standard management products.

MConsole can be used for message tracking, delivery reports and inter-personal notifications (enabling support of a Fire and Forget capability) as well as archive access. Statistics for message switching are provided using a Web interface to the Audit Database.


We welcome evaluations of our products and will make support resources available to you for the duration of your evaluation. Evaluation guides for all packages can be found on the relevant product evaluation page. You will need an evaluation password and a licence file which can be obtained by filling out this evaluation application form.