Failing IP communication across the network with 3750x

Question

Hi!
I'm facing a very odd problem. A week ago I've installed a 3750x on a client.
 On it, was connected, a Lan2Lan fiber channel(with IP associated directly to 
 the interface) and a MPLS link(over a Cisco 2901) interconnecting a branch, 
 and several HP v1910 L2 swtiches.
By the day of the activation, everything works great. I have at this first moment, 
configured static routes with IP SLA on the L2L link and, with higher cost on the 
MPLS due the larger bandwidth of the L2L. It worked very well, and the tests of 
redundancy were ok.
My problems started a couple of days after. First, I've lost the IP communication 
with the L2 switches from the stations, but, from the 3750x, they still were 
accessible(both telnet and ping).
And now, there's another problem. Because of a previous design, there are two 
gateways configured across the network, all the stations and some servers, 
use as the default gateway the IP 10.31.1.1, and several servers and other 
appliances where configured with the gateway 10.31.1.2. So, as a workaround, 
I had configured both address on the 3750x, the 10.31.1.1/16 as primary IP 
and the 10.31.1.1/16 as secondary IP, both are on the VLAN 1 yet, as all the 
devices. All the stations, servers and appliances are configured with 
this /16 mask. And, it is working.
The problem is, every time that the communications between the branches 
is changed from one link to the another, on some servers and appliances, after the IP SLA 
take away the route, the communications only occurs if I manually change the 
default gateway on the servers/appliance to the other IP, and, get back to the 
previous one.
Does anyone saw something like that?

Answer 1

Carlos
The short answer is you can't as far as i know. You need to do NAT to able to do this and i don't think the Nexus switches support NAT.
You need a device that can NAT both address ranges. If prod is always the one that initiates the connection then you need static NAT translations for the test machines and you can dynamicaly NAT prod addresses as they go into the test env.
But if both prod and test can initiate connections then you need to have static NAT translations for both sides.
We used a pix firewall for this when we connected our prod and test environments. A firewall is a good choice because you can make the test enviornment the outside interface where all traffic is denied by default. You do not want test affecting prod.
Jon