I’ve been asked several times if there is a way to get a host profile to stop prompting for MAC addresses.  This is actually pretty easy, although arguably not very intuitive.  Lets start with a quick example showing a host profile prompting for MAC addresses:

Depending on your environment you may see blank values for the MAC addresses (as shown above), in which case you will need to manually provide the values.  Or you may see the MAC Address fields populated with a default value.  This is because the default setting for how a host profile determines the MAC address is set to “Prompt the user for the MAC address if no default is available”.   What this means is:

  1. If the host was manually configured prior to attaching/applying the host profile, the wizard will use the host’s configuration to detect a default MAC address.  As such it will populate the field with a default value.
  2. If the host is unconfigured at the time the host profile is attached/applied (i.e. a new host booting via Auto Deploy), the wizard won’t be able to use the host’s  configuration to determine a default MAC address, and as such the field will be left empty requiring the admin manually enter the value.

In the first case, where a default MAC value can be determined, this default host profile setting is not not a big deal.  However, the problem is with the second scenario when there is no default and the filed is left empty.  As most admins aren’t in the habit of manually configuring MAC addresses it can be frustrating to have to manually enter them, especially when the virtual NIC will always have a default value that can be used.  And hence the question about how to get the host profile to stop prompting for MAC addresses.

Fortunately, it’s easy to reconfigure the host profile to stop prompting for MAC addresses.  Here’s how:

1)   Edit the host profile:

2)    Expand the Network configuration section and expand “Host virtual NIC”:

3)   For each virtual adapter change the “Determine how MAC address for vmknic should be decided” value to “User must explicitly choose the policy option”:

Once you are done, go back and edit the host profile and you will see that it no longer prompts for MAC addresses.

I think you’ll agree that the value  “User must explicitly choose the policy option” is not the most intuitive setting.  I’ll work on getting this changed to something more descriptive in the future.  Also, one caution that you’ll need to be aware of, anytime you update the host profile from the reference host the MAC settings will revert back to the default value of “Prompt user for MAC address if no default is available”.  This confused me for a while as I couldn’t figure out why the settings kept getting changed back to the defaults.

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About the Author

Kyle Gleed

Kyle Gleed is a Group Manager within VMware’s Integrated Systems Business Unit (ISBU) where he leads a team focused on the adoption and deployment of the solutions and capabilities of the Software-Defined Data Center. Follow Kyle on twitter @Kyle_Gleed