R3 to Oracle interface

Hi,

To create a B2B scenario, R3 --> XI --> Oracle Database......What are the adaptors used at the sender end and at the receiver end.

Is it right to use BAPI/IDOC at the sender end (for R3) and JDBC at the Receiver end.

But B2B scenarios are done through the firewalls. So, are IDOC/RFC and JDBC adaptors have security configurations?

If not, what adaptors can be used?

Thanks in Advance, I will assign points.