Is there a way to check which tnsname ADDRESS was used to connect to a database from within Oracle?

Hi,

Is there a way to check which tnsname ADDRESS was used to connect to a database from within Oracle?

I'm trying to find out if a Virtual IP address which can point to either a Primary or Standby server has been used on the primary and by whom.

For instance.

A VIP has been set up on server01 with name prod01.server,com and points to the server01 primary.

On a client host called 'client01', with ip 10.107.1.24 a tnsnames.ora entry with the host set to the VIP exists like.

PROD=

    (DESCRIPTION =

        (ADDRESS_LIST =

            (ADDRESS = (PROTOCOL = TCP)(HOST = prod01.server.com)(PORT = 1521))