Hyper-V MAC addresses

Hi,
I understand that each Hyper-v node in a cluster will have its own dynamic pool of MAC addresses that should be different between them. When a VM is started on a node it gets a MAC from this pool, if it's moved to another node and restarted it will get a
new MAC from the pool on that node. This is a concern for me as I don't want MAC addresses to change when VM's are restarted on different nodes, besides statically assigning a MAC address to EVERY single VM (which could be a fair few with the amount you can
host these days) is there any easier way to ensure once a VM has a MAC then it will always retain that MAC regardless of which node it is restarted on?
I am running Server 2012 R2 as the hyper-v host if that makes any difference.
Many thanks
Steve

Hi,
With Hyper-V you can configure a virtual machine to use a dynamic or a static MAC address for any given network adapter.
The default option is to use a dynamic MAC address – which means that Hyper-V will generate an initial MAC address for the network adapter, and it will regenerate the MAC
address if it believes it is necessary.
If you use static MAC addresses you need to manually specify the MAC address to use, but Hyper-V will never change it.
More information:
Hyper-V and Dynamic MAC Address Regeneration
http://blogs.msdn.com/b/virtual_pc_guy/archive/2010/05/14/hyper-v-and-dynamic-mac-address-regeneration.aspx
Hope this helps.
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Similar Messages

Router cannot see Hyper-V Guest MAC address

Greeting,
I have been trying to build a server on Hyper-V, on a host running Windows Server 2012 R2, and a wireless adapter is used.
A virtual switch was created as external, connected to the host's wireless adapter.
The guest OS is Debian 7, and the problem is it's unable to use DHCP to connect to the internet.
I have to manually specific an IP address and the subnet mask in order to access the internet in the Guest OS, say 192.168.0.50. And I set port forward to this IP for external connection to the guest, but then sometimes I cannot connect; without doing anything
it restores the connection after a while. At the same time I am keeping the MSRDP connection to tthe host so the host has not lost connecting to the internet.
When the server on Guest is not accessible from the web, I can still connect to the server within the host machine by typing the lan IP of the guest: 192.168.0.50
On checking the router, I found that two IP address 192.168.0.50 (Guest OS) and 192.168.0.15 (Host) are sharing the same MAC address (of the wireless card). It means the MAC address of the Guest OS is not seen by the router, and I suppose this is the root
for the instability.
Would you have any ideas about the situation, and suggested solution?
Thank you.

An update to my issue:
Just realized the possible cause: the (freaking) router is dropping inactive machine.
Basically the DHCP issue is not solved, but it doesn't seem to be a cause after all, as long as I manually assign the IP it works, even having the 2 IPs with the same MAC on the ARP table on router. (Host connection drop has to be further investigated).
As I found that the loss of connection actually happens after a while I don't touch the web server on VM, the longer I leave it idle the more likely I cannot connect to it again. The situation is like a prolonged loading when trying to access a website,
where sometimes you can connect after a while, or you never.
What's weird is, if I somehow manage to connect to the idle VM server by multiple attempts, and that after I have restored the connection, I can reconnect to the server from another computer very quickly without any significant loading time.
On some quick searches, I found someone using Linksys router is suffering from a similar situation as I do:
http://serverfault.com/questions/522448/application-request-routing-on-a-hyper-v-guest-intermittently-stops
So what I can try are basically 3 ways
-Change the router, not viable as I don't own it.
-Insert a wireless bridge in between
-Do something with Debian, making it periodically generate network request to the internet to keep the connection alive
Any ideas about my observation, and maybe possible solutions?
Thank you for reading.

Hyper-V Static MAC Address Best Practice

Hi guys,
Looking for some advice please..
We have several VM's running within a 6 node cluster that run an application which keeps losing it's license whenever the LAN MAC changes i.e. when the VM moves to a new node.
The obvious solution is to set these VM's with a STATIC MAC address however I have a few questions.
1. Is there a 'private' range I can use to ensure that we never see any conflicts?
2. What's the best way to implement this change? simply power off each machine and manually edit the settings or can I use SCVMM?
3. Will the VM's lose there current network card settings? static ip etc?
4. Will VM's set with a static MAC still fail over to other nodes?
Many thanks for your help
Robbie

For an answer you're much better off posting in the Hyper-V forum here:
https://social.technet.microsoft.com/Forums/en-US/winserverhyperv/threads
This forum is for Virtual Server 2005, no similarities to Hyper-V.

Hyper-V Failover Clustering MAC Address Question

Hello,
Can someone please explain how MAC address assignment works in a hyper-v cluster? I have a couple machines that need to have a static MAC address assigned and want to know how the cluster handles it when the VM is Live migrated to a new host. Thanks in advance.

Hi ice2921,
Yes, after export and import to another Hyper-V host, the dynamic MAC address of the VM changes
after export and import to another Hyper-V host, the dynamic MAC address of the VM changes, this is by design.
As Alexey offered article, to have a dedicated Mac Address for the VMs they should be set to static MAC address, it is normal the dynamic assign to vm when the all the Hyper-v
host as there own MAC address range , this is by design of Hyper V and failover clustering when using Dynamic MAC addresses for VMs.
If you are using 2008R2 Hyper-V failover and you found it often lost the network connection and configuration, please install the hotfix.
Reinstalled the integration services
The network connection of a running Hyper-V virtual machine may be lost under heavy outgoing network traffic on a computer that is running Windows Server 2008 R2 SP1
http://support.microsoft.com/kb/2263829
I’m glad to be of help to you!
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Hyper-V on Windows 8.1 is messing with MAC address when sharing my Wifi card

Hello,
I'm using Hyper-V on Windows 8.1 to build a complete SharePoint Development environment.
All of my VM are following this scheme:
a "local" private network shared between the host and all VM, using a static IP address plan (192.168.10.0/24)
a RJ45 external network, attached to my physical ethernet card. This network uses DHCP protocol
a WIFI external network, attached to my wireless network card. This network also use DHCP protocol
When plugged on the ethernet card, I have no issue. Both the host and the guest OSes are getting a valid IP address.
However, when I try to connect on the wireless card, I get some weird errors. Actually, my guest OS are getting the same IP address than the host. This issue an IP address conflict.
Someone else got the same kind of behavior : Windows 8.1
Hyper-V : IP address conflict on Guest OS
I've checked my MAC address plan, and it seems correct.
Using WireShark (a tool I'm not used to I admit), I can see that all DHCP request of the guest os, are sending the host MAC address, and not the guest' one.
Does anyone have an answer to this weird behavior?
Thanks,
steve
Paying back the community for its help by writing articles :
Have a Nice Day.Net Blog

Hi Steve,
Please try the following step and then retry ipconfig /renew in your VM :
1. Configure the WI-FI router to assign a static IP address to the host’s wireless network adapter(the IP should not be in DHCP Pool).
2. On the host, configure the wireless network adapter to use a static IP address. The IP address will be the same address configured in step 1.
3. Using Hyper-V Manager, create an external network switch that is bound to the host’s wireless network adapter
Hope this helps
Best Regards
Elton Ji
We
are trying to better understand customer views on social support experience, so your participation in this
interview project would be greatly appreciated if you have time.
Thanks for helping make community forums a great place.
Hi Elton,
First of all, thanks for your effort.
I will try your suggestion, but even if it works, it won't solve the actual root the issue.
Moreover, it is only relevant if I can control every wireless network I'm connecting to. What about if I travel and I connect with a customer wireless network? what about an hotel wireless network?
As I said, wireshark shows me DHCP requests using the wrong IP address. I strongly believe there's a bug somewhere between the wireless card driver and Hyper-v Mac-Bridge service.
Steve
Paying back the community for its help by writing articles :
Have a Nice Day.Net Blog

Windows 8.1 Hyper-V : IP address conflict on Guest OS

Hi ,
I have just installed Windows 8.1 and I want to move away from VMWare Player and use Hyper-V instead.
I have nevertheless issues with it on the networking side.
Before setting up my VM, I have:
- converted my vmdk to a vhd.
- created a virtual switch in Hyper-V Manager.
After that, i created the VM using the vhd and the virtual switch created beforehand.
Once I boot up the guest OS (Windows 7), I have no internet connectivity on the guest OS, and it says : windows has detected an IP address conflict
Also when I run ipconfig in a command prompt on the guest, I can see an ip address which is the same as my host OS (192.168.1.5) but then I guess that my host system takes the IP back as if i run ipconfig again the IP address is gone.
So I guess that my host and guest OS fight for the same IP. Also the message "windows has detected an IP address conflict" appears on the Guest OS.
Also at times, the guest OS receive a strange IP: 169.254.99.175 which I have no clue where it comes from.
Does anyone has an idea on how to solve the issue?
Also here is a screenshot of the configuration of the Virtual Switch :
Thanks for any help,
Francois

Hi Dan,
I guess that you use IP address reservation on your router (configuring your router so that DHCP always gives the same IP address for a particular MAC address).
As both your virtual machines and host machine will appear on the network as having the same MAC address, they will both get assigned the same IP by the router.
The solution is to turn off IP Address reservation. Another option is to assign a fixed IP instead of using DHCP.
I now here have 3 VMs on my Windows 8 machine, some use fixed IP and some use DHCP and they all work fine. The important part is to make sure your router does not have settings to assign a particular IP for a particular MAC address.
Good luck!
Francois
Thanks. Reservation is not configured in the router - I have the option of specifying a MAC address and assigning an IP, but the table is blank. I'm guessing it mayb defaults to it? It's a router from the local ISP.
In the advanced option of the virtual adapter in Hyper VM, I selected a static MAC. For whatever reason, the VM now has it's own IP address, X.X.X.7. Host is X.X.X.3
2 strange things though.
1. I can only access the router config page (X.X.X.1) via the VM. On the host, each time I try to login, it kicks me out. It's a Cox branded Netgear router (from ISP). Once I shutdown the VM, I can access the router config page on the host.
2. When looking at the list of connected clients in the router, it only shows the Machine name for the host - however, the corresponding IP address shown is that of the VM.
Weird ...
Anyway, not so concerned with having it work at home - it will be more so for at work.

Many warnings : prevented from using mac address because it is pinned to port

Hi
I am seeing my system log flooded (several per second) with event 28 warnings such as :
Port 'SWITCHPORT-SM-DB9DCFC7-E98D-438C-8998-CC0D9C14ED2B-1-1' was prevented from using MAC address '00-15-5D-00-B2-05' because it is pinned to port 'A0724966-695B-4552-B'.
Source : VMSMP
The environment is 2 X hyper-v 2008 r2 hosts. both have 4 NICs, 3 nics are connected to virtual switches and management OS is not allowed to share the network adapter, and then 1 NIC is obviously used by the host/mgmt OS and no virtual switch connected to
it. I am seeing the warnings on both hosts.
No load balancing or NIC teaming.
All VM's have their MAC addresses assigned dynamically and I cannot see any conflicting MAC addresses.
The warnings are logged for all or most of the MAC addresses and alternate between different "SWITCHPORT-SM-etc,etc" names.
Performance doesn't seem to be degraded, I've run continuous pings for more than an hour with no packet loss, just a single packet spike every now and then. Network access seems fine, Backup Exec 2012 jobs are succeeding, albeit somewhat slower than what
it was.
I don't know when it started, since these warnings have flooded out all else.
At first I thought it had something to do with a VM that I moved from one host to the other, where I copied the VHD accross and then created a new VM and assigned the original IP address to the new virtual NIC in the new VM. I then uninstalled the old hidden
NIC and restarted the VM in question, but that didn't stop the warnings.
Any ideas what could be causing this, or any tips on where I should start looking to isolate the cause ?

Got it fixed by creating new virtual switches, moving all VMs over to them, and afterwards deleting all the old virtual switches.
Still no idea what the cause could have been. How bizarre...

Windows Network Load Balancing - Virtual MAC Address

Hi All,
I have environment that running 2 Exchange 2010 server with CASHT and join windows network load balancing as a node.
My question is,
If NLB service is restart, is it virtual MAC Address for NLB will change to new virtual MAC Address?
Thanks for response,
Best Regards,
Henry Stefanus

Hi Henry Stefanus,
The NLB work mechanism will not change whether what higher application we used and I am not very familiar with Exchange NLB architecture, may the following KB and article
may help you.
When you use the unicast method, all cluster hosts share an identical unicast MAC address. Network Load Balancing overwrites the original MAC address of the cluster adapter
with the unicast MAC address that is assigned to all the cluster hosts.
When you use the multicast method, each cluster host retains the original MAC address of the adapter. In addition to the original MAC address of the adapter, the adapter is
assigned a multicast MAC address, which is shared by all cluster hosts. The incoming client requests are sent to all cluster hosts by using the multicast MAC address.
Selecting the Unicast or Multicast Method of Distributing Incoming Requests
http://technet.microsoft.com/en-us/library/cc782694(v=ws.10).aspx
The related third party article:
Building NLB Exchange 2010 RTM CAS / HT Servers (Hyper-V) – Part 1
http://blog.morecoffeeany1.com/2010/03/19/building-nlb-exchange-2010-rtm-cas-ht-servers-hyper-v-%E2%80%93-part-1/
I’m glad to be of help to you!
*** This response contains a reference to a third party World Wide Web site. Microsoft is providing this information as a convenience to you. Microsoft does not control these
sites and has not tested any software or information found on these sites; therefore, Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. There are inherent dangers in the use
of any software found on the Internet, and Microsoft cautions you to make sure that you completely understand the risk before retrieving any software from the Internet. ***
We
are trying to better understand customer views on social support experience, so your participation in this
interview project would be greatly appreciated if you have time.
Thanks for helping make community forums a great place.

How can I see the mac address table of a vSwitch

I am having some ARP collisions on my network and have determined that the offending mac address belongs to VMWare. I have already looked at the mac address tables of my physical switches but can't find the VMWare mac address I'm looking for. I would like to look at the mac address tables of the standard vSwitches to try to track down the root of the problem, but I fear that is not a possibility.
Does anyone know a method to display the mac address table on a vSwitch?

Hi midi25,
>>I would like to be able to see what devices are connected and if possible remove any stale entries.
Hyper-v virtual switch doesn't need us to manually maintain that "table" like a physical switch .
Best Regards,
Elton Ji
Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact [email protected] .

MAC addresses ofVirtual switches

I have the following lab environment:
1 server win2k12 r2 with hyper-v ( physical box )
1 server win2k12 dc ( virtual )
1 workstation win8 ( virtual )
I assigned the ip address 192.168.1.5 to the win8 machine and everything is okay and I am able to reach the internet.
I deleted the netwerk card and the added a new network card to the win8 machine.
I assigned the same IP address to it.
However, the computer is unreachable now.
If I recreate the virtual switch everything if okay.
I think it has something to do with the MAC address table of the virtual switch.
I think that it is linking the 192.168.1.5 IP to the old MAC address of the netwerk card before I deleted it.
How can I delete this cache and is there a way to read this cache?
Your help would be much appreciated.
Andre

What does this mean? "However, the computer is unreachable now."
What do you see if you issue ipconfog /all?
Have you physical connectivity?
Can you ping by IP and by name?
What is configuration of your networkm, namely the client (is you client member of domain)?
Fro my question you can see that what is clear to you need not be clear to readers. Better description of system and its response and error loga may iincrease the convergence to functional sysstem.
Regards
Milos
BTW: What you want to achieve by removing NIC?
Sorry for not being complete in my question.
The IP settings are just fine as they were before and I am a 100% certain that they are correct. However if I use the same IP address as used on the previous NIC ( which I deleted ) then I just can't access ( not even a ping, no it is not an issue with the
firewall ) anything not even the hypervisor. If I use another IP in the same range then everything is working correctly ( can ping the hypervisor and access the internet for example ). I can't explain it and I don't have the lab environment set up anymore
so I am unable to provide you with statistics. I hoped that I was over seeing something and you could point it out to me with the litle information provided.
So in short what I did.
1- create a vm and a add a nic and link it to an external switch
2- ping the hypervisor from the vm
3- Delete the nic from the vm
4- Add a nic
5- Configure the identical settings ( ip, subnet, gateway etc )
6- Unable to ping the hypervisor.
Andre

How to make mac address gmail contacts overwrite the ones on my HTC Android phone - I don't want to sync - that makes the phone scramble and overwrite my computer. I want to remove or correctly overwrite the phone information as I have done with iPad.

Please help - I am beginning to hate google, my android and gmail. I have just wasted about 5 hours in a futile attempt to try and get my current Mac contacts list on my computer updated to my phone. I'm not that computer literate but I have looked up about google phone accounts, vCards, backing up contact lists, what SD on phones are, and God know what else. I have searched the internet and tried all sorts of things and I still have a mac with a now correct contact list (after the iPad contacts scrambled it and I spent ages manually correcting them all) and a phone with an outdated contact list. If you try and sync them the phone wants to overwrite the computer one just like the iPad did (would it be so **** hard to give you a choice on the phone as to which overwrites which!). After all the advice on the internet failed, I got the bright idea to completely delete all the ones on the phone and if it was empty of contacts the computer one could be exported to it. Not as simple as it sounds. First I backed up (I think) my computer contacts list. Numerous futile attempts to go through the phone options to globally delete all contacts did not work - they gave a warning message and you got to choose whether to continue or not, I did, and it looked like it might be working as it changed to zero data on the phone, but then they all popped back up again from God knows where from, but without their little added bits like pictures of the people. So, I tried un- syncing the darn phone from google and then deleting them globally. That didn't work either. I tried deleting them all again and again and google would crash and not let me do it. It is absolutely ridiculous that this is so damned difficult to do (especially if you are not computer savvy) and that you cannot choose which device overwrites which when syncing. I gave up and ticked sync with Google again (not that it appears to do anything to the phone contact list at all). So after 5 hours I am back to where I started from, with a phone showing all the same incorrect contacts (but the pictures are back), which wants to overwrite the computer if I try any sort of sync, and no way to fix them except go into each one manually and try and do it - and how long would that take (and I've already wasted hours and hours fixing scrambled contact lists!). I think I will do a print out of the computer contact list and just carry it around with me like an address book - so much bloody simpler. So now I have a headache, am fighting an overwhelming urge to hurl the phone at the wall, hoping for a heat wave to evaporate icloud things and am wishing I had bought an iPhone instead of the stupid HTC Android. Can any one offer me any suggestions on how to get rid of the contacts on my phone and replace them with the ones in my mac address list - hopefully after that they can sync to their hearts content and not stuff everything up again (which was why I unsynced google a while back - because the phone's list kept making stuff ups and scrambling and duplicating my computer contacts list). Am I the only one on the planet having this problem or is there someone else out there who has had it and solved it.

Without "pretending" to be yourself on the other phone (change settings) there's nothing else you can do.
iOS devices are meant to be single user and can't view iCloud.com the same way a Mac or PC can do.
You need to find a desktop or laptop machine (Mac or PC) to log in at iCloud.

I want to reserve a static IP address on my Airport extreme. What is the difference between reserving by MAC Address and DHCP Client ID?

I want to understand the differences in the way you can reserve a static address for a device on the network. I had previously set the device itself to an address and then reserved it with DHCP Client ID, which I thought was just the devices static addresss. I'm not sure if this was in fact correct or just happend to work. I know what a MAC address is, but I'm not really sure what the DHCP Client ID is. So it would be great if someone could clarify it, and the difference between reserving address by MAC Address or DHCP Client ID.

A MAC address is a unique identification consisting of letters and numbers in a form that looks like this:
xx:xx:xx:xx:xx:xx
Every network device has a MAC address, which can be found on a label on the bottom or back of the device. Apple calls this the Ethernet ID.
A DHCP Client ID is an optional name that you can assign to a device. For example, on your Mac....
Open System Preferences (gear icon on the dock)
Open Network
Click on Ethernet
Click Advanced at the lower right
You may be able to edit the DHCP Client ID here....for example.....you could enter MJ500's MacBook in the space provided. That would be the Client ID of your Mac.

I have two .mac addresses; how does this work in iCloud?

This is not about consolidating Apple ID's... I think.
When I got my first .mac address, I thought I picked a good one at the time. Later on, due to the peculiar spelling, I opted for an additonal (paid) address which I use every day. Now the first one (which is an Apple ID) contains my calendars, contacts, etc. I never use the email portion of it, again because of challenging spelling. The second .mac address (also an Apple ID) is an email only account. This is the email account I use daily.
When I make the transition to iCloud, I intend to keep my original AppleID (from the pre-.mac days) as my iTunes store ID.
My question is, what happens with my two other accounts?
.mac #1 with the contacts and such would move to iCloud and sync everything there as it currently does with MobileMe. Since .mac #2 is an email only account, would I even need to bother moving it to iCloud (if that's even possible), or would I just keep using that as email only using the current mail settings on my iThingys and Mac? Does anyone know if .mac #2 will live on after MobileMe vanishes, or will I loose my daily and coveted .mac email at that time?
I'm sure Apple has a good reason for not allowing us to just consolidate everything in one place, but I know there are many out there with a similar situation to mine.
I've spent a good deal of time tonight searching the various threads and can't seem to find an answer to the two .mac email dilemma. My appologies if it's already been discussed.
To sum up, I have one Apple ID that I use for iTunes and intend to keep as such. I have two .mac addresses which are also Apple ID's; one that syncs with MobileMe and one that is email only. I would like to use iCloud to sync what is currently on MobileMe, AND continue to use the simpler email address that I've been using for years.
Am I screwed??
Thanks in advance for your help, and Happy Holidays to all!!

Migrate the account which contains your calendars, contacts etc. first, at http://me.com/move and set it up on your Mac and devices.
http://www.apple.com/icloud/setup/mac.html
Now migrate the email-only account in the same way. On a Mac you can add it in System Preferences>Mail, Contacts & Calendars - it won't sync anything but will be added to the accounts in Mail where you can then use the email in the normal way.
I don't know what the equivalent process on an iOS device is; very likely you need to add it as an account in the Mail app.

How to find a workstation object by ip or mac address?

Hi gang.
I'm trying to search for a workstation object by mac address or by IP
address. So far, I'm not able to find the correct attributes to do so.
Can anybody point me in the right direction to find a workstation by either
IP or mac?
thanks!
John

[email protected] wrote:
>
> Hi gang.
>
> I'm trying to search for a workstation object by mac address or by IP
> address. So far, I'm not able to find the correct attributes to do so.
>
> Can anybody point me in the right direction to find a workstation by either
> IP or mac?
In ConsoleOne find, advanced, look for ZEN:INV IP Address attribute
-sk

How do I add my phone's Wi-Fi Mac address to my home server so that I can use my home Wi-Fi with my phone?

Hello. I am using an Android cell phone and, though the phone sees my home server name and accepts my password, it won't connect. I understand that I may have to add my phone's Wi-Fi Mac address to my home server in order for it to allow my phone access, but I have no idea how I might do that. Could someone help me with this? Thank you.

Tdalso wrote:
How do I add a phone number so I can use either my US or Canadian number (depending on where I am) with iMessage and Facetime on both my iPhones?
You need to log out of iMessage and Facetime, make sure your number is correct in Settings/General/About, then log back in again to send a new activation request.

Hyper-V MAC addresses

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