orbitron
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Contributor

Is it Possible to Expose Physical NIC to Guest OS?

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Hello,

I'm using some software that needs low-level access to a NIC, but am having trouble finding docs / previous discussions about doing this, which leads me to believe it isn't possible with ESX.

Are their any docs / discussions that pertain to exposing / reserving a single NIC to a single guest OS? Essentially every packet that hits this NIC needs to be un-manipulated by the ESX server prior to reaching the guest OS (Win2k3)

Thanks,

~ Jon

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khughes
Virtuoso
Virtuoso

I was thinking the problem would come on the switch, but I guess it would be an interesting concept to try. But then if this was the case wouldn't it be isolated to a single ESX host because if it was migrated anywhere else there would be two different locations for that MAC address, and then if that's the case it goes back to maybe that box shouldn't be virtualized for that software to work. If you're going to lock it down to 1 host and that 1 NIC it might work but I can't see how that's better than just having a physical piece of hardware.

  • Kyle

-- Kyle "RParker wrote: I guess I was wrong, everything CAN be virtualized "

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jbruelasdgo
Virtuoso
Virtuoso

in ESX, you have to connect a VM to a vSwitch, which needs an uplink to a physical NIC

so I do not think you will be able to direct a VM the way you want

Jose

Jose B Ruelas http://aservir.wordpress.com
khughes
Virtuoso
Virtuoso

Like Jose said with ESX there is always that hypervisor that sits between the actual hardware and the virtual machine. The only way to really isolate one physical NIC to a vm is to make its own portgroup and assign it to that specific NIC but data will still stream through the esx host prior to arriving at the VM.

  • Kyle

-- Kyle "RParker wrote: I guess I was wrong, everything CAN be virtualized "
orbitron
Contributor
Contributor

Thanks for the replies,

One last thought, the vswitch has 1 physical NIC with a MAC address different from what the Guest OS MAC will be. What happens if I force the guest OS virtual network adapter MAC to be the Physical MAC address?

Thanks,

~ Jon

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khughes
Virtuoso
Virtuoso

I'm a bit rusty on my Cisco networking and all that but a MAC address is kind of like a IP address just on a different layer of the TCP/IP stack so I would think having 2 MAC addresses the same on the same network would cause some major issues. Would there be any way to point your software to the virtual machines MAC address?

  • Kyle

-- Kyle "RParker wrote: I guess I was wrong, everything CAN be virtualized "
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mcowger
Immortal
Immortal

I honestly dont know what would happen in that case - it would be interesting to do.

The MAC of the physical NIC is usually never seen on the network, so I'm not sure if it would work or not.






--Matt

VCP, vExpert, Unix Geek

--Matt VCDX #52 blog.cowger.us
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mcowger
Immortal
Immortal

That wouldn't be so much of a problem. Usually that an issue because the same mac would be seen on 2 ports, which pisses off the CAM table on the switch. In this experiment though, they'd be on the same port....






--Matt

VCP, vExpert, Unix Geek

--Matt VCDX #52 blog.cowger.us
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khughes
Virtuoso
Virtuoso

I was thinking the problem would come on the switch, but I guess it would be an interesting concept to try. But then if this was the case wouldn't it be isolated to a single ESX host because if it was migrated anywhere else there would be two different locations for that MAC address, and then if that's the case it goes back to maybe that box shouldn't be virtualized for that software to work. If you're going to lock it down to 1 host and that 1 NIC it might work but I can't see how that's better than just having a physical piece of hardware.

  • Kyle

-- Kyle "RParker wrote: I guess I was wrong, everything CAN be virtualized "

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orbitron
Contributor
Contributor

You guys are right, looks like nothing works properly if I force the external MAC to be the guest OS MAC.

This system will just have to be on a physical box, not a big deal.

Thanks for all the insight though!

~ Jon

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