Set your Domain Controller Sites up

If you have 2 Domain Controllers and you want them to behave according to your subnet, go here:

Administrative Tools -> Active Directory Sites and Services.

Now set up your Sites (e.g. Berlin, London) and add the sites Subnetz to it (e.g. 1.1.1.0/24 and 2.2.2.0/24)

That should tweak your DC network...