[cups.general] How to set the network interface for outgoing print jobs

[Steve Bergman]

I have a machine with a real eth0 address of 192.168.1.1.

Over this interface, I have an openvpn tunnel 10.6.0.1<->10.6.0.2, and a
route to the 192.168.6.0/24 network on the other end of the tunnel.

When cups sends lpd jobs to a printer on that end, the source ip address
is 10.6.0.1.  I need it to be 192.168.1.1 for them to be accepted.

How can I specify an outgoing interface for these jobs?

Forwarding is set properly for such packets to get through.

For example, if I ping the remote side, the packets appear to come from
10.6.0.1.  But if I use "ping -I eth0" to force the interface, they
still get through and have the desired source ip.

Thanks for any assistance,
Steve Bergman