Wheter the network of a domain controller is classified als domain network doesn't depend on the gateway configuration.
The behaviour of a false network classification can be caused the
NLA (network location awareness) service
starts before the domain is available. In this case the public or private network is choosen and not corrected afterwards.
How to check if this fault situation is given
When the domain controller after rebooting is in the public network, restart the NLA service or disconnect / reconnect the network. The domain controller should be in the domain network afterwards.
How to solve it
It may help to set the NLA Service to delayed start. Better, check why the domain needs long to be present. It seems that the domain needs longer to start when there are multiple network cards.
When it doesn't help
When neither speeding up the loading of the domain nor the delay of NLA help and the error is caused by the long loading of the domain (look: "how to check..."), then there are some more things that can be done.
- Restart the NLA service manually after every reboot
- Write a skript for restarting it an run it with the scheduler (dangerous)
- Shift the loading of the NLA service to the end of the service starts, changing the load order in the registry (dangerous)
One more cause can also be when the domain controller has two or more IPs configurated (on the same or on other network cards) and the additional networks aren't configured in the DNS.
Reproduction of the behaviour
On a test domain controller (single DC!) I deleted the default gateway entry and set the
DNS Server to
delayed start. Doing this the domain needed long to get loaded and the network was classified as
public. After disconnecting and reconnecting the network cable, the network was classified correctly as