Virtual Ethernet Adapter / Multiple MAC and IP address for one adapter

ethernetnetworkingvirtualizationwindows 7

I need to emulate multiple (10+) Ethernet adapters (different MAC and IP, same subnet) through a single Ethernet adapter. I know you can assign multiple IP addresses to a single adapter, but haven't found any solution for multiple MAC address. I am currently doing this by using Linux VMs under VirtualBox with bridged virtual adapters. However, this solution is not optimal for my applications.

I would like to know if it is possible to do the same without a virtual machine setup.

Edit:

Found something for Linux: Multimac, hopefully someone will point me to a Windows based solution.

Best Answer

This is by no means tested, but the tuntap driver that OpenVPN uses works under Windows. You can use it to create "virtual" adapters.

Having read through this article/software page, I don't see why you wouldn't be able to change the MAC of each of these virtual adapters in the registry as described.

Related Solutions

Virtual Machines – Safe Range of MAC Addresses for Virtual Machines

There are actually 4 sets of Locally Administered Address Ranges that can be used on your network without fear of conflict, assuming no one else has assigned these on your network:

x2-xx-xx-xx-xx-xx
x6-xx-xx-xx-xx-xx
xA-xx-xx-xx-xx-xx
xE-xx-xx-xx-xx-xx

Replacing x with any hex value.

Linux – How to set up internal routing between virtual interfaces and real ethernet interface (Linux)

Solved it, finally: It's an ARP related issue.

The DHCP server assigns an IP address to the virtual interface MAC address and sets this pair in the server's local ARP table
The Linux box ties the new IP address to the virtual interface that requested it.
PINGs are working on both ways:
When pinging from Linux to server, it goes out through the real interface (which is on the same IP subnet)
When pinging from server to Linux, again the real interface responds so it seems as if everything is OK...

BUT

When the server sends IP packets (in my case, SNMP messages) it uses the virtual interface's MAC address. When it reaches to the Linux box, the kernel just discards these frames, since it doesn't know how to forward them; Running Wireshark displays these messages since usually the interface is put in promiscuous mode

In order to make the SNMP messages reach the SNMP agent which is bind to the virtual interface, the IP packet must have the real interface's MAC address (I think that only then the kernel does VLAN routing, based on the IP address...)

The way to achieve this, is to send a gratuitous ARP request from the Linux' box real interface to the server, stating that the newly assigned IP address (to one of the virtual interfaces...) is "owned" by the real interface's MAC address. This updates the server's ARP table correctly.

BTW, this also explains why waiting some time before starting the SNMP traffic works: the server's ARP table entry is aged out, so the server sends an ARP-request which is responded correctly by the real interface

Best Answer

Related Solutions

Virtual Machines – Safe Range of MAC Addresses for Virtual Machines

Linux – How to set up internal routing between virtual interfaces and real ethernet interface (Linux)

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