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Active Directory Domain where FQDN and NetBIOS name are the same

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I have "inherited" an
ancient domain (NT4, then upgraded to Win2000 Mixed Mode and now running on Win2003)
where the NetBIOS name coincides with the DNS/FQDN one, and this is giving us problems
with remote clients which need to be joined to the
domain.



Lets the domain be called
EXAMPLE: it is both the NetBIOS
name and the DNS name, as can be seen by opening the DNS
administration panel. Inside the local LAN, apart some occasional confusion on what
protocol is resolving the machine's name, this arrangement seems to
work.



On remote LANs (connected by VPN),
problems happen: the remote client can not connect to the domain. The error message
states that the DNS query correctly returns the domain controller list, but no domain
server can be contacted. From a connectivity standpoint, all ports are opened inside the
VPN, so this is not due to ACL and the likes.



Rather, using Wireshark to examine the
exchanged packets, I can see many (failed) NBNS queries - in
other words, the remote PC is using NetBIOS broadcast resolution method to find the
domain controller. This is clearly going to fail, as NetBIOS is a non-routable protocol
by design.



In short, it seems that when entering
a NetBIOS-style domain name in the "Member of domain:" GUI panel, Windows only uses
NetBIOS to resolve/find the domain controllers, with no DNS fallback. In some manner,
this can even expected: after all, EXAMPLE is not a valid DNS
name (however, I wonder why the domain creation wizard let this happen in the first
case, but I digress...).




So
work-around the problem, I tested some
solutions:




  • sidestep the
    problem entirely, joining the PC to the domain when it is on our local LAN for OS
    installation/preparation (it clearly can not be done for client already deployed on
    remote locations)

  • use an appropriately-crafted
    lmhosts file

  • installation and
    use of WINS



The last
approach (WINS) seems clearly better, as it avoid distributing a (potentially changing)
lmhosts file to the remote clients. However, I would like to
solve the problem once for
all.




So, my questions
are:




  • can I
    force Windows to use DNS names rather than NetBIOS (note: I already tried to disable
    NetBIOS name resolution on the NIC properties page, with no
    avail)

  • can this situation be normalized without radically
    change the current domain?

  • new one:
    can I add something like a "DNS domain alias" to assign a correctly-formed FQDN name to
    the current AD domain?

  • can the domain be renamed? If so,
    what problem can I expect doing that?

  • if all the above is
    "no", is the best approach to create a new domain, gradually
    migrating the current client/server on the new
    one?




Thanks.



Answer




WINS/Netbios name resolution should never be used for anything due to the
security risks. Additionally, when Netbios name resolution is enabled, Windows always
performs a Netbios/WINS lookup concurrently with DNS lookups regardless if the name is
available in DNS or not. If the environment does not have any products or applications
that would fail due to a domain rename, that may be an option.



You may want to read up on single-label DNS
name support:



href="https://support.microsoft.com/en-us/help/300684/deployment-and-operation-of-active-directory-domains-that-are-configured-by-using-single-label-dns-names"
rel="nofollow
noreferrer">https://support.microsoft.com/en-us/help/300684/deployment-and-operation-of-active-directory-domains-that-are-configured-by-using-single-label-dns-names



href="https://blogs.msmvps.com/acefekay/2009/11/12/active-directory-dns-domain-name-single-label-names/"
rel="nofollow
noreferrer">https://blogs.msmvps.com/acefekay/2009/11/12/active-directory-dns-domain-name-single-label-names/




Unfortunately you are working with a
version of Windows (2003) that is no longer supported. A more contemporary test would be
to use the GlobalNames zone for flat/single-label name resolution, but you don't have
that.


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