RFC registered program

[MSteiner]

Dear all,

We have an RFC destination with a gateway registered program which belong to an external server/application.

So, if that external server change the IP address, do we have to re-register the program with rfcexec in our gateway again or SAP will update the IP address and details using the hostname we provided ?

BR

[Ulrich_Schmidt · Accepted solution]

From your question I gather, that you have not yet fully understood, how a registered RFC server works. The answer is basically: you have to do nothing... 😉

> do we have to re-register the program with rfcexec in our gateway again or SAP will update the IP address
> and details using the hostname we provided ?

Neither one. First of all: rfcexec cannot be used to register another program!! rfcexec registers itself at the SM59 destination and would then receive all RFC calls that the SAP System sends to that destination. This is not what you want, right: you still want your own program (external application) to receive those RFC calls...

Also a registered RFC server does not work with IP addresses! (In fact, you can register several different programs on different servers/IP addresses at the same SM59 destination, and then the SAP System will do "load balancing" and distribute the RFC calls evenly to all the registered receivers.)

So all you need to do is to start your external application on the new server/IP address, and everything will work as before. Nothing needs to be changed in SM59 or on SAP side or in your external application.

Edit: I just realized that there is one case, where the SAP side indeed has to be adjusted, when an external RFC Server moves to a different IP: if you have secured the SM59 destination with an ACL entry in the gateway's reginfo file (see the documentation about "reginfo" in help.sap.com/doc/saphelp_nw75/7.5.5/en-us/e2/16d0427a2440fc8bfc25e786b8e11c/frameset.htm), and this ACL explicitly mentions the IP from which receiver programs are allowed to register, then you need to update the ACL entry with the new IP, so that the external program will again be allowed to register on the gateway.

[thomas_mller13 · Accepted solution]

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[Ulrich_Schmidt · Accepted solution]

MSteiner said nothing about the ProgramID being changed, he only said the IP address would be changed (I assume the external application, which has so far been receiving the RFC calls, is moved to a new hardware/VM.) I repeat: in that case nothing needs to be changed in SM59!

And I think you are mixing up two different concepts here: of course the registered Server program needs gateway hostname and gateway service (as defined in SM59), but the SAP system does not need the IP address of the external Server! So here also nothing needs to be changed, when the external program is moved to a new IP address: just start the external program on the new machine (using same GWHOST and GWSERV as before), it will connect to the gateway as before, and the SAP system can send RFC calls to it as before. You see: nothing needs to be changed, even though the registered Server program is now running on a different IP!

This is what I mean by "registered RFC servers work without IP addresses": the SAP system does not need to know the IP address of the receiving system. (As opposed to other types of RFC destinations, where the sending system needs to know the IP address of the receiving system.)
(Trust me: I have been working in SAP's RFC dev team since 1998... 😉)

Edit: but I have to admit, there is one exception to what I have said above: if the gateway reginfo feature is used to secure the registration, then the reginfo file may need to be adjusted, when the external server moves to a new IP. I will update my answer above to reflect this case.

[thomas_mller13 · Accepted solution]

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[Ulrich_Schmidt · Accepted solution]

The "setup the connection of the RFC-Server to the SAP system" does not change at all, when moving the RFC Server to a new IP address.

[MSteiner · Accepted solution]

Thank you Ulrich_Schmidt for the clarification. It was very helpful. BR Max

[thomas_mller13]

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[MSteiner]

Hi thomas_mller13,

[MSteiner]

What do you mean with update RFC destination. In the RFC (SM59) I have a destination only with the name of the program. But that is a program registered in our SAP gateway and nothing else. The question is if the external program must be re-registered again in the SAP gateway or not, after the server hosting the external program changed the IP .

[thomas_mller13]

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[Ulrich_Schmidt]

This is wrong. You don't need to update the RFC destination. See my answer above.