MQTT

Description

The MQTT service enables message passing over a Data Diode. It connects to a broker on the source network and copies messages, for the configured topics, to a broker on the destination network. Messages received from the source broker will be sent with the same retain-flag to the destination broker.

Supported versions

The following versions of respective protocols are supported by the MQTT service:

Protocol	Supported version(s)
MQTT	3.1.1

Configuration

In this section, the MQTT service parameters are described in detail. Parameters are divided into sections, MQTT Client Upstream and MQTT Client Downstream, in the same way as they are displayed when configuring the service using the DD Manager.

note

In DD Manager, as well as in the parameter descriptions below, mandatory parameters are indicated by asterisks (*).

MQTT Client Upstream

General parameters

Parameter	Description	Format
Topics *	A list of topics for the service to subscribe to.	Array of strings
Quality of Service *	The Quality of Service level for all subscriptions set up by the service.	Available options: At Most Once (0), At Least Once (1) and Exactly Once (2)

Connection parameters

Parameter	Description	Format
Address *	Address of the remote host, either an IP address or a hostname.	Internet host name, see RFC 1123, section 2.1
Port *	TCP port that the service use to connect to the remote host.	Integer within range 1 - 65535
Client ID *	A unique ID for the client to connect with.	String
Keepalive interval *	The interval between keepalive packets. If interval is 0, sending of keepalives is disabled.	Integer (seconds)

TLS

Parameter	Description	Format
TLS *	A selection of TLS modes is available. If set to TLS With Defaults the service will use built-in default certificates.	Available options: Off, TLS With Defaults, TLS With CA and TLS With Client Certificate
CA *	File containing the CA certificate in PEM format. This option is available when TLS With CA is selected, and allows you to upload your own trusted Certificate Authority that the service will use to validate the MQTT broker.	File
Client certificate *	File containing the client certificate in PEM format. This option is available when TLS With Client Certificate is selected.	File
Client key *	File containing the client key in PEM format. This option is available when TLS With Client Certificate is selected.	File

Authentication parameters

Parameter	Description	Format
Authentication type *	A selection for which type of authentication the service will use with the MQTT broker.	Available options: Anonymous, Password.
Username *	Username to be used when authenticating towards the remote server.	String
Password *	Password to be used when authenticating towards the remote server.	String

MQTT Client Downstream

General parameters

Parameter	Description	Format
Topic prefix *	A string to add onto the start of topics before publishing them to the destination broker. This parameter is optional.	String
Quality of Service *	The Quality of Service level for all messages published by the service.	Available options: At Most Once (0), At Least Once (1) and Exactly Once (2)

Connection parameters

Parameter	Description	Format
Address *	Address of the remote host, either an IP address or a hostname.	Internet host name, see RFC 1123, section 2.1
Port *	TCP port that the service use to connect to the remote host.	Integer within range 1 - 65535
Client ID *	A unique ID for the client to connect with.	String
Keepalive interval *	The interval between keepalive packets. If interval is 0, sending of keepalives is disabled.	Integer (seconds)

TLS

Parameter	Description	Format
TLS *	A selection of TLS modes is available. If set to TLS With Defaults the service will use built-in default certificates.	Available options: Off, TLS With Defaults, TLS With CA and TLS With Client Certificate
CA *	File containing the CA certificate in PEM format. This option is available when TLS With CA is selected, and allows you to upload your own trusted Certificate Authority that the service will use to validate the MQTT broker.	File
Client certificate *	File containing the client certificate in PEM format. This option is available when TLS With Client Certificate is selected.	File
Client key *	File containing the client key in PEM format. This option is available when TLS With Client Certificate is selected.	File

Authentication parameters

Parameter	Description	Format
Authentication type *	A selection for which type of authentication the service will use with the MQTT broker.	Available options: Anonymous, Password.
Username *	Username to be used when authenticating towards the remote server.	String
Password *	Password to be used when authenticating towards the remote server.	String