How to stop open relay in SAP

Hi Experts,

Recently I got a security alert for open SMTP relay on port 25000 in our server.I checked for it and got the result as given below.

netstat -Aan|grep 25000

f1000e00337b3bb8 tcp4       0      0  *.25000               *.*                   LISTEN

Can you please let me know how to stop the incoming mail service on this port.

Thanks

Aditya Roushan