TCP/IP RFC Connection Failed after EHP 7 Upgrade
Recently we have upgraded to ERP 6.0 EHP 7. The upgrade was smooth as butter until we encountered a serious issue that the third party gateway RFCs are not working.
Strangely, in SMGW–> Logged On Clients, we could see the entries for the Registered IDs and the corresponding IP addresses of the third-party servers.
To cross-verify, we logged on to the third-party windows machines and checked/restarted the necessary services and re-checked SMGW. Entries were available in SMGW but RFCs in SM59 fail as “Program Not Registered“.
After some internet surfing (I can’t remember the source at this time), I have encountered a parameter gw/acl_mode. After setting the parameter to 0 instead of the default value 1, all the RFCs worked like a charm. No more changes required.
I believe the reason behind this is that, after EHP 7 Upgrade SAP has changed the default value from 0 to 1 to add more security. Value 1 indicates that only the Application servers of the same system can communicate with each other but not the external machines. But for the external Registered Programs to work through TCP/IP RFCs, this needs to be set as 0. 0 is no restriction on the Registered machines/External servers.
However, SAP recommends that the value 0 should NOT be set in the Production environment. So please do not do so until you are definitely sure that the external server is completely secure and the program from the third party is really necessary as part of Production Operations.
The parameter is dynamic and therefore direct change to profile does not need a restart. You might wanna go through below threads to better understand what you are up to.