The short version of the question: How to bridge 2 interfaces so all traffic directed to one is passed to the other.
wlan0 A RT2500 card that is working just fine and is this box's only connection to the LAN and beyond. Active and DHCP-configured on boot.
eth0 An ethernet port on the system, that also works well, but has no cable plugged in. Autodetected by Fedora, and autoconfigured. Inactive on boot.
Program Doe A fictional name for a very real program. It is persisting on attempting to access the Internet through eth0, even though eth0 is not configured or active.
The long version of the question: Program Doe needs access to the Internet. But I cannot change Program Doe's config to use any other port than eth0. Is it possible to create a bridge of some sort, so that when Program Doe attempts to use eth0, the data is transfered through wlan0 instead?
What I've tried so far:
Thrashing the config files for Program Doe in a futile attempt to have the program use wlan0.
Program Doe forums. (It would seem that the writers of Program Doe never gave a glance at the idea that not everyone would have eth0 active.)
Finding a replacement for Program Doe.
Open for suggestions. Thank you.