The IGS RFC and HTTP listener must be configured to be prepared for requests.
In Version 6.40, the configuration for the standalone and the integrated version was done in the configuration file igs.xml.
From IGS Version 7.0 on, the configuration for the integrated version is done in the instance profile of the SAP Web AS. Note 844669 describes the configuration in the instance profile.
All necessary parameters have default values in the C-kernel.