RFC: TCP/IP Connection - Start an External Program on an Application Server
For an RFC destination of type TCP/IP connection that is configured to start an RFC server program on an application server, the work process that calls the RFC server program starts the program directly. Once the RFC server program is running, it establishes a TCP communication channel back to the application server's gateway. To establish this channel, the program uses the parameter values that it received over the command line upon process creation.
When SNC is active, the work process that starts the program sends the SNC information to the RFC server program in additional parameters. Therefore, the external server program can use the application server's SNC configuration and credentials to protect the TCP-based communication channel with SNC.
In this scenario, the AS ABAP is the initiator of the communication and the external program is the acceptor.
To specify the SNC options for the initiator (AS ABAP), use transaction SM59. See Maintaining RFC Destinations and their SNC Options Using Transaction SM59.
You do not need to specify any additional SNC options for external programs that start on an AS ABAP. The programs retrieve the SNC information that they need as follows:
- SNC mode and QoP
The SNC mode (active or inactive) for the connection and the quality of protection are defined in transaction SM59 for the initiator and automatically sent to the program to be started.
- Name and location of the external library
The external program finds the name and location of the external library (SNC_LIB) in the application server's profile parameter snc/gssapi_lib.
- SNC name for the external program
The AS ABAP uses the SNC name of the application server where the program is started as the SNC name for the external program. The external program is a child process of a work process on the application server and therefore has the identical security environment as the parent work process. This is the only way the AS ABAP system can make sure that a valid SNC name is provided for an external program that may run on several different application servers.