METHOD 1:

Suppose you want to debug a function module which is there in SRM/APO system from R/3.

(FYI: As you all know this RFC Destination is maintained via transaction code SM59 )

Keep the external break-point in your calling PROGRAM before it calls the RFC. Now LOGIN into the Destination system where you’re remote enabled function module exist and put an external break-point.

Now go to Transaction code SRDEBUG and click on the Activate Debugging Button: It will give you a pop up which confirm your id, application server etc.

Click enter which will give you another popup. Keep it as it is.

Now go to your Report program in source system and Execute it , it will open debugger , when you press F5 key to go inside the RFC Function module it will start debugging in APO system.

METHOD 2. Calling a custom RFC 

Three steps needs to be followed.

For example we are calling an RFC enabled FM in ECC system from CRM system.

• ADD an infinite loop in the remote custom Function Module (adding a “DO. ENDDO.” statement at the start of the FM would be enough). 
• Execute your program in the CRM system. The execution STOPS at the RFC call, because of the infinite loop. 
• Now login to the ECC system and go to transaction SM50 select the process which is executing the RFC and navigate to the menu: “Program/Session->Program->Debugging” this triggers the debugger session in a SEPARATE window. 

METHOD 1:

Suppose you want to debug a function module which is there in SRM/APO system from R/3.

(FYI: As you all know this RFC Destination is maintained via transaction code SM59 )

Keep the external break-point in your calling program before it calls the RFC. Now login into the Destination system where you’re remote enabled function module exist and put an external break-point.

Now go to Transaction code SRDEBUG and click on the Activate Debugging Button: It will give you a pop up which confirm your id, application server etc.

Click enter which will give you another popup. Keep it as it is.

Now go to your Report program in source system and Execute it , it will open debugger , when you press F5 key to go inside the RFC Function module it will start debugging in APO system.

METHOD 2. Calling a custom RFC 

Three steps needs to be followed.

For example we are calling an RFC enabled FM in ECC system from CRM system.