Samba4 (A global catalog (GC) cannot be contacted)

I’ve been experimenting with Samba4 as an Active Directory Controller. I got it running and was able to join with a Windows 7 workstation. I did however run into some problems. Here they are with their solutions:

• Problem: When clicking “Member of” in Active Directory Users and Computers->#domain#->Users->#username# you get the error message “A global catalog (GC) cannot be contacted. A GC is needed to list the object’s group memberships. …”
  Solution: Make sure you have the Active Directory Controller in the list of DNS servers on the client before your other DNS servers/router.
• Problem: Joining the domain fails.
  Solution: Use the realm part of the domain. If your domain is “MYDOMAIN.LOCAL” then join using “MYDOMAIN”.