IP Networking

Not sure if this considered traffic shaping or not, so I'll appreciate the enlightenment...

Setup- Mac Pro, Mac OS X 10.5.6, Crashplan Pro Backup server.
the Mac Pro has 2 E-net ports, en0, en1.
Both E-net ports are connected to the same network, different IP's.

Problem-
We are planning to use this machine as a backup server for about 20 computers. We are backing up the data to the Mac Pro, where Crashplan is compressing it into a single file and storing it temporarily. We are then moving that file from the Mac Pro to our enterprise NAS, which is backed up regularly. This process is actually working quite well, with one exception: the amount of traffic created on en0 is extremely high with it trying to communicate with the client side computers and the NAS storage simultaneously.

What we want to do is use en0 for the backup of the client machines, and en1 for transferring the compressed Crashplan files to the NAS. SO, in theory, something like this:
en0- All traffic generated by Crashplan
en1- All traffic generated by [some service that I don't currently know because I can't get access to the computer's owner]

I -think- I can do this with route and ifconfig, but I'm not 100% how to.
man route/man ipconfig is unfortunately not helping as much as I'd like, and my Googlefu is failing me right now.

Hopefully someone can provide a point or two to some examples that I can start from.


Thanks in advance
Phil

I'm learning everyday, and more than willing blow something up if it helps me learn more...

Phil Benware
Harvard Medical School

Followup/additional Info.

Crashplan is performing both the incoming and outgoing data transfer services. The connection for the outgoing data transfer to the NAS fileserver is over SMB.