Unlike a traditional DICOM service which treats DICOM as messages, Nexus treats DICOM as a stream and is therefore extremely memory efficient. In order to receive DICOM from external systems, the DICOM Stream Input Node needs to be started on a specified port to process any inbound DICOM requests.
Nexus can start multiple DICOM services with each one requiring an available port. It is possible to enable the secure socket option which would require connecting systems to establish communication on a secure socket connection but this is not supported by many systems.
The DICOM input node can be configured as might be expected in that the service AET (and aliases) can be set, other DICOM peers can be configured and the service can be configured to accept specific SOP classes and transfer syntaxes.