When a sender specifies only daemon, without network and service, a receiver with similar settings can see messages on a given subject.
However if the sender specifies the daemon explicitly, and network with service, then the receiver (which specifies only daemon, and empty network and service) cannot see messages on subject or _LOCAL.subject - why is that?
And what would be the significance of _LOCAL (not routing beyond the daemon) for listening to subject or LOCAL.subject as long as everyone connects to the same daemon explicitl?
When a sender specifies only daemon, without network and service then it is using the following configuration :
. specified daemon
. default network (';' = the default broadcast address of the machine)
. default service = 7500
To be able to exchange Rendezvous messages applications need to share the same configuration (same network and service, two different daemons can be used if they are not running on the same host ).
This means that if an application is using a specific configuration (different from the default) that it defined explicitly and another application is using the default configuration they cannot communicate.
Message sent using the _LOCAL subject prefix remain local on the daemon used by the Publisher application, only Subscriber applications connected on the same daemon can receive this message (if they are subscribed to the prefixed subject).