Keepalive/Firewall

I have a third application behind a firewall that talks to an oracle
database server. The application server opens a connection to the DB on
startup and the firewall closes the connection after an without activity.
The next time the app tries to talk to the database, it fails. I set the
KeepAliveTime registry key to 30 minutes but that didn't seem to work. Is
there anything else I can try or is there anything I can do at the OS level
to keep this connection active, such as writing a vbs or exe that can do
this? Any assistance would be greatly appreciated.

Current Setup
App --> Firewall --> Oracle DB