Basic VMWare Question

Unanswered Question
May 22nd, 2010

Hi, folks:

When one creates a VM and associates an application with it, does that VM have an IP address assigned to its own vNIC?  So, if there are 5 VMs running on one physical server, how many IP addresses will you have? How does the physical NIC's IP address assignment relate to the others?

For example, in a physical server config that has two NICs, the IP  address is bound to the active NIC (lets assume I am doing NIC teaming),  and each NIC will also have a MAC address. So, for that physical server, I would have 1 IP  address and 2 MACs, correct?

So, in the 5 VM example, lets assume each VM has 2 vNICs, then I should  have 5 IPs and 10 MACs altogether in that box -- this is just for the  VMs. Is this correct?

Victor

I have this problem too.
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Giuseppe Larosa Sun, 05/23/2010 - 05:30

Hello Victor,

I see from network point of view that on an active VMware NIC I can see the BIA and some MAC addresses using specific OUI that are owned by vmware:

000c.29

or

0056.50

see also

http://www.vmware.com/support/esx21/doc/esx21admin_MACaddress.html

as a result of this new VMware devices may appear as unauthorized hubs because multiple MAC addresses are learned in a switch port (we have a script running that checks all switch ports looking for this event).

Also, when for some reasons an ESX host switches to other NICs I see the MAC address flapping messages for some of VMware MAC addresses, this may mean that our colleagues set the MAC address manually as explained in the link above.

>> NIC teaming

be aware that they can mean different modes with NIC teaming we had long  talks with server people about this.

Hope to help

Giuseppe

Ganesh Hariharan Sun, 05/23/2010 - 06:59

Hi, folks:

When one creates a VM and associates an application with it, does that VM have an IP address assigned to its own vNIC?  So, if there are 5 VMs running on one physical server, how many IP addresses will you have? How does the physical NIC's IP address assignment relate to the others?

For example, in a physical server config that has two NICs, the IP  address is bound to the active NIC (lets assume I am doing NIC teaming),  and each NIC will also have a MAC address. So, for that physical server, I would have 1 IP  address and 2 MACs, correct?

So, in the 5 VM example, lets assume each VM has 2 vNICs, then I should  have 5 IPs and 10 MACs altogether in that box -- this is just for the  VMs. Is this correct?

Victor

Hi Victor,

Assigning an ip address will be as long as your physical subnet is bridged to the VMs and the IP's thats been allocated are on the same subnet, then you would assign them as you would with a physical server.

All  the virtual network devices share the following characteristics:

• They have their own MAC addresses and unicast/multicast/ broadcast filters.

• They are strictly Layer Ethernet adapter devices.

Hope to Help !!
Ganesh.H
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