[CentOS] What on Centos is wiping out my eth0 IP address every 5 minutes?

[Rock]

On Tue, 23 Jul 2013 23:03:00 -0700, John R Pierce wrote:

> you should be able to get 300 feet of mostly open space with a simple 
> panel antenna

Understood. The Nanobridge M2 may be far more than I need.
But, it should work as it's advertised to go five miles.
All I need is a few hundred feet.

I'll try to keep on topic though. 

I think my "original" problem was what you guys sensed from 
the start. 

It was supremely frustrating having my manually typed eth0
IP address being wiped out - but - apparently that was what
Network Manager was supposed to do.

Apparently Network Manager was set to pick up a DHCP address
for eth0, and, when none were forthcoming, it wiped out the 
existing IP address.

I only need to figure out now how to switch gracefully between
using wlan0 connected to the home broadband router inside the 
house, and using eth0 wired to the Nanobridge M2 outside the 
house.

I tried setting eth0 as suggested and left wlan0 alone, but, 
that killed the inside-the-house connection immediately. 

I'm still debugging why that happened (I had figured they're 
two totally separate cards); but maybe you can't have to NICs
connected to the same net at the same time?

Is there an easy way to tell which NIC is being used for a
connection? Or to tell one NIC to win over the other?