Windows Server 2012 r2 Hyper-v 2 External Switches

Question

I wish I could have a setup as the following:

1. I have Windows Server 2012 R2
2. I have Two NICs: First one is connected to the LAN and the second one connected to the Internet
3. I have Created two external virtual switches: First one for the LAN NIC and the second one for the Interne NIC
4. I have create one virtual machine and promoted it to domain controller with DHCP working properly. This virtual machine has the LAN external switch.

When I create another Virtual Machine using the second external switch I got connected to the internet inside this second virtual machine.

When I add one more adapter to the second virtual machine from the LAN switch. I can not access the internet from that machine.

My question is:

How to access the internet in a virtual machine that has two adapters one from external switch to the LAN and the other with external switch to the Internet?

Answer 1

I guessed when you added the 2nd adapter, it have the default gateway setup also that either override the existing default gateway or have better metric, then Internet traffic route through to internal switch. You can verify it by check all destination "0.0.0.0" routes by command "route print".

If it is the case, remove the default gateway of 2nd adapter (and reset the gateway for the original adapter when need) can make the Internet traffic route back to external switch.