RFC Connection Error

[RakeshPatel]

Hi Everyone,

We are facing below error when we do RFC call from SAP Commerce Cloud to On-Prem SAP ECC system.
We have NAT configured at both side. 
Also we are using the Azure VM to forward request to On-Prem system using nginx.
SAP Commerce Cloud -> AzureVM nginx -> On-Prem SAP ECC

Error Details

Script execution has failed [reason: com.sap.conn.jco.JCoException: (102) JCO_ERROR_COMMUNICATION: Initialization of destination MANAGEMENT failed: Connect from SAP gateway to RFC server failed
	connection parameters: TYPE=A DESTINATION=MANAGEMENT ASHOST=<NAT IP> SYSNR=00 PCS=1

LOCATION
    SAP-Gateway on host <HOST NAME> / sapgw00
ERROR
       timeout during allocate
TIME
        Mon Dec 16 14:10:29 2024
RELEASE
     753
COMPONENT
   SAP-Gateway
VERSION
     2
RC
          242
MODULE
      /bas/753_REL/src/krn/si/gw/gwr3cpic.c
LINE
        2218
DETAIL
      no connect of TP sapdp00 from host <NAT IP> after 20 sec
COUNTER
     2
]

 #CCV2 SAP Commerce Cloud  #ECC #RFC 

Thank you.

[mansurarisoy · Accepted solution]

It seems that your issue is similar to the one described in the question, "RFC failure from Commerce Cloud to On-Premise ECC" and I believe the solution I provided for that question should resolve your issue as well. Please give it a try and let me know if it works.

[RakeshPatel · Accepted solution]

Yes, I tried the same steps but it didn't work for me.
We don't have direct VPN connectivity between Commerce Cloud and On-Prem servers.

We have AzureVM between Commerce Cloud and On-Prem server.
SAP Commerce Cloud -> AzureVM nginx -> On-Prem SAP ECC

Do you think same steps will work for above connectivity?

[mansurarisoy · Accepted solution]

Yes, I think it’s related to the configuration of NAT IPs. The answer Kai provided might also give you a direction to explore.

[Former Member]

Hi,

in case you are using for the RFC connection logongroups , then you need to do a couple of additional steps:

1) Set up VPN from CCv2 to customer network, add remote systems and NAT rules for all required message servers and (!) application servers.

2) Define a new logon group in the SAP system, add the required application servers and maintain the NAT IPs on logon group / application server assignment. (optional)

3) Add host aliases for the message servers and configure the message server connection in the RFC Destination configuration in Commerce Backoffice. Use the logon group defined in step 2.

4) For every application server, add the NAT IP to parameter gw/alternative_hostnames in the instance profile.

Some explanation:
If instance profile parameter gw/alternative_hostnames was not maintained, the gateway process does not recognize that the connection should go to itself, so it tries to forward it to the NAT IP which wouldn't work in the customer network. With gw/alternative_hostnames maintained, it recognizes that the IP belongs to itself and establishes to connection with the application server.

KBA for more details: https://me.sap.com/notes/1760329

Best Regards,
Kai