Like many IT Professionals and enthusiasts, I have a lab. Mind happens to sit on my laptop and various components will be spun up / down / torn apart as I need.
One I happened to keep together was my Domain Controller. Sure they're not difficult to spin up and bring online with Windows PowerShell.
But this particular one I had MDT and WDS on there. I used it as a standalone appliance for Deploying Server 2016 as I needed. It works and works well.
Last night I fired it up and went to deploy a Server 2016 box only to find out nothing was grabbing an IP address.
I checked over logs and scanned through. Active Directory was good but over and over DHCP was complaining it couldn't find an Active Directory controller... on the same box.
I did a bit of digging in our local forums and ran across a user with a similar issue. If you looked at the DHCP Server it showed up as a 169.x.x.x (IPIPA) address. Running Ipconfig I couldn't see it anywhere but this user mentioned that the issue turned out to be a second network card, with no cable attached. The answer was "Disable the NIC"
Sure enough on my Virtual box I had a second NIC I installed and forgot about. Disabled it internally on the server, bounced once and life was good.
Silly me, I should have cleaned up my old NIC's 🙂