In this tutorial, which is a special case, I will explain how to solve the 404, 407 and 408 error that can occur on a DNS server with Windows Server under the following conditions:
- Being on a virtual machine
- Being on a Hyper-V host
- Have configured NIC teaming, which is configured as an external virtual switch with management enabled.
If you are in this particular configuration, it is possible that on your DNS server, you encounter the error 404, 407 and 408 at the level of the DNS server:
After several searches on the Internet and on the Microsoft doc, a resolution of this error is proposed here:https://docs.microsoft.com/fr-fr/troubleshoot/windows-server/networking/events-407-408-in-dns-server-event-log
Not fitting in this case, so I continued my research, having another DNS server running on another hyper-v host and this one having no problem, so I decided to look on the side of the Hyper-V host that hosts the DNS server that has this error.
Almost at the same time, on the Hyper-V host, an error is logged: MsLbfoSysEvtProvider (16945), which indicates a MAC address conflict.
After some research, this is a known problem at Microsoft and occurs when using network card teaming, which is used as a virtual switch WITH management enabled.
In a PowerShell command prompt, use the following cmdlet:
Get-NetAdapter | sort MacAddress
As you can see the MAC address of the “active” card is used on:
- The Virtual Switch (Teaming)
- The virtual network adapter (Ethernet (VM)) that is attached to the host.
Now that the observation is made, this problem must be solved, for this there are several solutions:
If the Hyper-V host is under Windows Server 2012R2 and +: it is possible to modify the MAC address of the Teaming cardhttps://social.technet.microsoft.com/wiki/contents/articles/31357.hyper-v-troubleshooting-mac-address-conflict-event-16945.aspx
If the Hyper-V host is running Windows Server 2016 or newer, configure teaming with a SET switch : https://rdr-it.io/hyper-v-commutateur-virtuel-avec-agregat-de-port-switch-embedded-teaming-set/