Once you have your account structure setup in SAP BTP Cockpit, navigate to Global-account → Sub-account → Space. Afterwards click on SAP HANA Cloud from the menu on the left side of the screen.
For the candidate SAP HANA Cloud instance, navigate to Actions → Open in SAP HANA Cloud Central.
A new tab will be opened for SAP HANA Cloud Central Cockpit and your list of instances will be displayed for a selected space. From Actions column, click on the 3 dotted icon.
Select Edit from the menu.
From the new wizard, kindly navigate to Connections section and here you can either allow all incoming connections or allow only specific IP addresses/IP ranges. You can also opt to deny all connections.
Once changes are done, click on Save button and you are done.