I've just moved from a general NOWTV standard issued router which when using it's DHCP service had no issues allocating individual IPs via my Host laptops single shared Ethernet NIC to the several established HyperV client operating systems I run Microsoft HyperV external Switch setting.


Now since migrating to the Draytek 2862ac router and using it as a DHCP server, it keeps assigning duplicate already assigned IPs it's given to initially detected HyperV clients on my laptop, the same IP.

It's as if it cant detect the individual MAC addresses of the HyperV host has issued the hyperV clients as they come online and stops at the actual HOSTING laptop with the physical shared NIC's parent MAC address.

Im not a network guru, so forgive me if using the terms incorrectly, but can the Drayetk 2862ac 'span' further down & differentiate between the the HOST laptops shared NIC MAC address to the deeper HyperV clients Mac address? (Or why isnt it recognizing that the HyperV packet is stemming from a sub-MAC address?

Note:
When looking in the Drayteks DHCP table or ARP cache, it's always registering the HOST laptops physical MAC address. (So I seen my 5 virtual machines Netbios name all associated to my HOST laptops physical MAC address)
I also dont want to statically assign IPs to my HyperV clients as I move between 2 locations when WFH and the Office & it was seamless before when Home (NOWTV DHCP router) & Office DHCP. (the office still works fine with detecting the MAC clients).

Update, ...ARP table is fine with regards to registering the physical NIC of the HOST machine's MAC address to the respective HyperV clients IP addresses, as it acts as a switch then naturally it needs to know its routing (Arping) to the HOST MAC.

The issue if the DHCP table after about the first 2 (out of 5) virtual machines I bring online, then the Draytek DHCP starts not being able to detect the virtual MAC addresses fromt he HyperV external switch eg: 00-15-5D-00-0E-04 (00-15-5D is MS HyperV) , but then starts allocating the HOST servers physical MAC (The HyperV external Switch only) to the netbios/DNS host names of the Virtual machines instead of no longer detecting them from their assigned HyperV virtual MAC addresses.

Its like it falls over when there is more than 1 or 2 virtual machines with a virtual HyperV MAC address coming routing via the 1 physical host machines MAC address (which is the HyperV external Switch setting).

??????

Note: Again there are no such problems when using any other DHCP hardware, including my broadband providers own provided router/DHCP combo box of tricks.

Suddenly started behaving itself, . . very strange.

I was trying loads of things at once, so may have been:

- configuring HyperV to not share the vNIC to the HOST OS 🤔
- Resetting each of the Virtual machines own NICs and re-configuring the dual DNS of both locations of my home & office environments (AS I still applied custom DNS, it was only gateway and IP + subnet which I took from the DHCP in both locations).

Anyway, all working now and no more dual IP assignments of already assigned IPs causing conflicts.

👌👌

Absolute confirmation on what caused this issue now identified & resolved

The Bridge NIC which Windows HyperV creates on the Host OS was somehow enabled on the checkbox for TCP/IP protocol when it is NOT supposed to be, only the vEthernet Switch NIC which deploys in the HOST OS NIC settings is supposed to have TCP/IP enabled.

Corrected - no problems since.