SAP Application Server System still goes over wrong Network Adapter

Hello experts,

WE recently did a DMO from Oracle to SAP HANA. SAP HANA now runs, of course, on a different physical host than the SAP Application Server. Both hosts are connected via different network adapters

-. Frontend Adapter with 1 Gbit/s - is only a fall back connection between Application Server and HANA, the interfaces are used for users and administrators to connect via frontend (SAP Logon, SAP HANA Studio)

- Backend Adapter with 10 Gbit/s. This adapter should actually be primarily used for communication between SAP Application server and HANA.

Here are the ip adresses and hostnames of all adapters

Now, when I measure on the SAP Application server with command lines like

OS>netstat -an | grep <backend IP of SAP HANA>

OS>netstat -an | grep <frontend> IP of SAP HANA>

OS>iftop -i eth0

OS>iftop -i eth1

Then I see that there is no connection on eth1 (backend) from SAP application server to SAP HANA. The system uses the slower Frontend Adapter and I want to change that whitout doing any magical tricks with some iptables rule oder fumblin around in the /etc/hosts, because that would be the ugly way.

So what I did was:

• change PAramter sAPDBHOST in DEFAULT.PFL of SAP System from hanafrontend to hanabackend
• changed primary host name on SAP HANA via command line
  OS>hostname hanabackend
• used hdblcmgui to rename SAP HANA primary hostname from hanafrontend to hana backend

HANA is a single host system, so SAP HANA internal commnication is set to "local".

I restarted both systems, even sapstartsrv, and did cleanipc <SAP instance> remove and slibclean on SAP Application server because it's AIX.

But the SAP application server still uses the frontend adapter to connect to SAP HANA, even though when I look in the developer traces, for example in the log of dev_w0, it says "trying to connect to SAP HANA database running on hanabackend". So the correct hostname is being recognized. Why does it still use the frontend adapter?