Routing and Directly Connected Interface
I'm using version 2.0.3. I have a LAN interfaces with a single, directly-connected 10.5.200.0/23 subnet. I have a second LAN interface that routes to 300+ networks, including 10.x.x.x subnets. Can I route 10.0.0.0/8 out the second LAN interface without causing problems on the 10.5.200.x interface? Is it good practice to do so?
You can, directly connected takes precedence over static or routes from routing protocols.
I do it all the time, without problem, don't know if it's best practice, might depend on who you ask :D
While it is best to avoid such overlaps, more specific routes do get considered first as SeventhSon mentioned. It should work fine.