How to determine and setup IP, MAC address in both physical and virtual machines

Posted on 2011-05-08
Medium Priority
Last Modified: 2012-06-27
Developing a small production datacenter and as we deploy virtual machine after machine, we're getting the knack for P2V and now looking to wholesale virtualization of entire enterprise as part of modernization (ERP system is running on HPUX 10.2 from ~1994.)  All the backstory to reinforce that in general we're good at keeping systems healthy and recovering from disaster and getting good at virtualization.  The more we know the more we go for.

The problem/question as we start hardening up the new server farm (more like patio garden for some but big to us); how do we access and know what all the physical and virtual IP and MAC address informationnis?

We'll have pieced together as many as 10 physical servers and an NAS storage unit and most of them have two NIC's apiece; then many of the virtual machines were physical conversions and they have networking "memories" of their physical self and then virtual NIC's added during P2V process.

Bottom line is we're grappling with how to apply physical NIC, MAC & switch thinking in our new virtual world and in several instances we can't get virtual machines to connect normally outside their new environment.  Is there or is there a better way to know and/or static assign physical IP and MAC and virtual IP and MAC assignments in all cases?
Question by:VirtualDallas
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LVL 125
ID: 35716352
If you look at the information of the network interface card in properties of the virtual machine you can find out the virtual network interface assigned to the Virtual Machine MAC address, and you can also if you wish assign a static MAC address there also.

This is by using the vSphere Client GUI.

Also, using a third party too for free Veam Free Reporter, you can run reports of the same http://www.veeam.com/vmware-esx-reporter-free.html.

LVL 125

Accepted Solution

Andrew Hancock (VMware vExpert / EE MVE^2) earned 1000 total points
ID: 35716391
Personally, I also think this is one of vSphere vCenter biggest weaknesses of managing a large estate of virtual machines the ability to report on machine configurations.

VMware Community Pack Networking Info
VMware Community Pack Networking Info
VMware Community Pack Networking Info

VMware Community Pack Networking Info

I would recommend using the following, also VMware recommends the use of PowerCLI, which is PowerShell interface with vSphere-specific additions. You'll be able to find IP addresses and MAC Addresses very easily, and Network Information available to you at a glance.


One of the simplest PowerCLI examples, and something which is actually extremely useful on its own, is the Get-VM cmdlet. Which lists VMs.

PowerCLI can be a bit overwhelming to use,  But it can be enhanced with a nice toolset and a library of preconfigured scripts to jump-start your mass changes, which is possible with PowerGUI



VMware Community Pack


It's also worth looking at The free VMware Guest Console


The free VMware Guest Console, an experimental application created by VMware Labs, is a great tool for managing vSphere VM processes and files. You can view, sort and kill processes across all VMs, and you can also run a script on all Windows or Linux VMs.

Author Comment

ID: 35716638
Still digesting all the information but appears huge help.  Glad i wasn't just too old school to understand things like "assinging" a MAC address.  Still a freaky concept, but thats life in vworld.  At first (second and third) glance most above adrresses finding & knowing IP & MAC.  Anything that simply assigns IP to physical and virtual?   Apolgies if its there and just haven't dug in deep enough and thank you.  Again, huge help.
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LVL 125
ID: 35716674
If you want to assign MAC addresses to a Virtual Machine (I would strongly advise against doing this unless you have reasons, Port Security, Network Load Balancing for Uni or Multicast), you must do it via vSphere Client GUI, check the Virtual Machine properties, edit the Network Interface, and specify the MAC address you want to use there, but is MUST be a valid VMware MAC address of the format 00:50:56:00:00:00 to 00:50:56:3F:FF:FF.

Generally, we just let VMware auto generate them, and record them in database.




As for changing the physical MAC address of the host, this is not configured by ESX, it's a hardware function.

Author Comment

ID: 35716788
OK; have studied the links on your post and understood about MAC addressing, not a need but a curosity.  Will avoid.  Static addressing IP's is the one more common on physical machines and elusive in vSphere.  But before I beat it to death; we'll go ahead with Power \GUI & Community Pack.  With some patience & practice, I bet we'll get it, now that you've guided us to them and counseled that it wasn't "just us" in the virtual IP addressing challenge.  Borh are good to know and huge help.  Thank You.
LVL 125
ID: 35716847
But when you install a physical server, you just "accept" it's mac address, you don't usually change it!

So when creating a MAC address, one is generated for you, which you can record, so is there any difference between physical and virtual?

Author Comment

ID: 35716983
I guess the piece I'm missing is the two NIC's on one server; but I havent studied NIC teaming enough and haven't applied the 2nd NIC on sandbox installs, yet.  What I'm finding is MAC Addresses on my Domain Controller tied to IP's that DHCP assigned.  The IP's are virtual machine access IP's, but to confound all; we're running an .ovf of an IBM Server technology called Cast Iron which doesn't expose its operating system through the console well.  So Cast Iron is not connecting and not sure where it got/gave DHCP the MAC addresses for the IP's and would prefer not to use DHCP at all; but struggling to know where all the virtual addresses were coming from and you seemed to help enough to get me back on track, tomorrow.

Bottom line is ist a combination of taking a big bit in new IBM Data Integration technology, upgrading an acient ERP system and virtualizing all when we never have before.  Good news is we're a resourcefull bunch here in Tesas and with genuine help from talented folks like yourself, we'll get 'er done.
LVL 125
ID: 35716995
any other specific VMware issues there are enough VMware Experts here to answer your questions. So just post your questions.

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