ARemote Function Call(RFC) is the call or remote execution of a Remote Function Module in an external system. In theSAPsystem, these functions are provided by theRFCinterface system. TheRFCinterface system enables function calls between twoSAPsystems, or between aSAPsystem and an external system.

How to Configure and Test RFC.This tutorial is divided into 4 sections1. Setup a RFC connection2. Trusted RFC connection3. Testing a RFC connection4. Error ResolutionProcedure to setup an RFC connection:Enter Transaction CodeSM59In the SM59 screen, you can navigate through already created RFCs connection with the help of option tree, which is a menu based method to organize all the connections on the basis of categories.Click the 'CREATE' button. In the next screen , Enter - RFC Destination Name of Destination (could be Target System ID or anything relevant) Connection Type here we choose one of the types (as explained previously) of RFC connections as per requirements. Description This is a short informative description, probably to explain the purpose of connection.After you'SAVE'the connection, the system will take you to 'Technical Settings' tab, where we provide the following information: Target Host Here we provide the complete hostname or IP address of the target system. System Number This is the system number of the target SAP system. Click SaveIn the'Logon and Security'Tab, Enter Target System information Language As per the target system's language Client In SAP we never logon to a system, there has to be a particular client always, therefore we need to specify client number here for correct execution. User ID and Password preferably not to be your own login ID, there should be some generic ID so that the connection should not be affected by constantly changing end-user IDs or passwords.Mostly, a user of type 'System' or 'Communication' is used here.Please note that this is the User ID for the target system and not the source system where we are creating this connection.Click Save. RFC connection is ready for useNote: By default a connection is defined as aRFC. To define a connection as tRFC or qRFC go to Menu Bar -> Destination aRFC options / tRFC options ; provide inputs as per requirements. To define qRFC , use the special options tab.Trusted RFC connection

There is an option to make the RFC connection as'Trusted'.Once selected, the calling (trusted) system doesn't require a password to connect with target (trusting) system.

Following are the advantages for using trusted channels: Cross-system Single-Sign-On facility Password does not need to be sent across the network Timeout mechanism for the logon data prevents misuse. Prevents the mishandling of logon data because of the time-out mechanism. User-specific logon details of the calling/trusted system is checked.The RFC users must have the required authorizations in the trusting system (authorization objectS_RFCACL).Trusted connections are mostly used to connect SAPSolution ManagerSystems with other SAP systems (satellites)Testing the RFC ConnectionAfter the RFCs are created (or sometimes in case of already existing RFCs) we need to test, whether the connection is established successfully or not.As shown above we go to SM59 to choose the RFC connection to be tested and then we expand drop down menu - "Utilities->Test->". We have three options:

Connection test ->This attempts to make a connection with remote system and hence validates IP address / Hostname and other connection details. If both systems are not able to connect, it throws an error. On success it displays the table with response times. This test is just to check if the calling system is able to reach the remote system.

Authorization Test ->It is used to validate the User ID and Password (provided under 'logon and security' tab for the target system) and also the authorizations that are provided. If test is successful, then same screen will appear as shown above for the connection test.

Unicode Test ->It is to check if the Target system is a Unicode or not.Remote Logon >This is also a kind of connection test, in which a new session of the target system is opened, and we need to specify a login ID and Password (if not already mentioned under 'Logon and Security' tab). If the user is of type 'Dialog' then a dialog session is created. To justify the successful connection test, output will be the response times for the communication packets, else error message will appear.What went wrong?If somehow the RFC connection is not established successfully, we can check the logs (to analyze the issue) at OS level in the 'WORK' director. There we can find the log files with the naming convention as "dev_rfc" and the error description can be read from such files.