With the help of the following Stackoverflow answers here and here I was able to successfully connect to the system DBUS remotely over TCP/IP.
And using D-FEET I'm able to verify the connection.
As can be seen by the above screenshot, i'm able to access the remote bus, and i'm able to successfully call the org.freedesktop.hostname1 object and its interfaces.
But while attemtping to access the com.aldogroup.Calculator, I get the following exception thrown
This AccessDenied also occurs when accessing other services such as the org.bluez (I haven't been able to find a pattern)
UPDATE
My system.conf file
<busconfig>
<listen>tcp:host=0.0.0.0,port=55557,family=ipv4</listen>
<listen>unix:tmpdir=/tmp</listen>
<auth>ANONYMOUS</auth>
<allow_anonymous/>
<apparmor mode="disabled"/>
<policy user="root">
<allow own="com.aldogroup.Calculator"/>
<allow send_destination="com.aldogroup.Calculator"/>
<allow send_interface="com.aldogroup.Calculator"/>
<allow send_type="method_call"/>
</policy>
</busconfig>
DBUS busctl output
root@aldogroup-dart-6ul-1b6be6:~# busctl introspect com.aldogroup.Calculator /com/aldogroup/Calculator
NAME TYPE SIGNATURE RESULT/VALUE FLAGS
com.aldogroup.Calculator interface - - -
.Divide method xx x -
.Multiply method xx x -
org.freedesktop.DBus.Introspectable interface - - -
.Introspect method - s -
org.freedesktop.DBus.Peer interface - - -
.GetMachineId method - s -
.Ping method - - -
org.freedesktop.DBus.Properties interface - - -
.Get method ss v -
.GetAll method s a{sv} -
.Set method ssv - -
.PropertiesChanged signal sa{sv}as - -
Best regards,
Simon