Problem:
If like me you are tring to add an alias to an existing computer so you can access it via two different DNS names and you receive the below message, then read on;
“You Were not connected because a duplicate name exists on the network. Go to System in Control Panel to change the computer name and try again”
Solution for Server 2000, 2003, 2008:
First in DNS create a CNAME record instead of a normal Host(A) record.
The next thing to do is to create a new DWORD key in the registry
On the server open regedit and navigate yo:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters
Create a new DWORD with the following details:
Value name: DisableStrictNameChecking
Data type: REG_DWORD
Radix: Decimal
Value: 1
Then reboot the Host.
Solution Server for 2008 R2:
First in DNS create a CNAME record instead of a normal Host(A) record.
The next thing to do is to create a new DWORD key in the registry
On the server open regedit and navigate yo:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters
Create a new DWORD with the following details:
Value name: DisableStrictNameChecking
Data type: REG_DWORD
Radix: Decimal
Value: 1
Next on server create SPN's for the flat name and the fully qualified name of your cname alias
Open up a command prompt and run the below
setspn -A host/<your_ALIAS_name> <ServerrName>
setspn -A host/<your_ALIAS_name.domain.com> <ServerNname>
Then reboot the Host.
References:
http://support.microsoft.com/?id=281308
http://www.clydesdalesoftware.com/blog/10-02-25/CNAME_rsquo_s_and_SPN_rsquo_s_Access_Denied_Error.aspx
Comments
This doesn't appear to work. Server = 2008 R2, Client = XP
Thanks for the comment,
That is good to know, so far I have not had a need to implement it yet on R2.
There must be a similar method, anyone have any ideas?
I will see what I can find....
I have not been able to varify it the below works or not but it may be of some use?
I fould it here
CNAME’s and SPN’s: Access Denied Error
Clydesdale Software
February 25, 2010
In a previous post I talked about adding a registry key to disable strict name checking which was more of reminder than anything else for when the error “A Duplicate Name Exists”. On a previous server this was all that needed to be done but on a new server with Windows Server 2008 R2 I found I also needed to add a spn using setspn. I first received and error of a domain trust failure when trying to access a cname’d network share but then when I did a net view I received an access denied error.
To register the SPN for the DNS alias (CNAME) records, use the Setspn tool with the following syntax:
setspn -A host/your_ALIAS_name computername
setspn -A host/your_ALIAS_name.company.com computername
After registering the spn everything is working fine.
From Karan’s Blog:
“You must register the Kerberos service principal names (SPNs), the host name, and the fully-qualified domain name (FQDN) for all the new DNS alias (CNAME) records. If you do not do this, a Kerberos ticket request for a DNS alias (CNAME) record may fail and return the error code KDC_ERR_S_SPRINCIPAL_UNKNOWN.”
Let us know if it works?
Hi there to every body, it's my first pay a quick visit of this web site; this web site contains amazing and in fact excellent material in support of readers.
Whats up guysn!
I have been requested to configure an alias for a server so that users can
map a drive using the alias instead of the host name.
I have a 2003 domain in native mode. In the dns server setting up a new
CNAME record with the name of Testro for a record that already exists in
DNS (the record is a "file server")
When I go to cmd prompt on a client computer, I can ping the name and Testro
successfully resolves the IP address of the file server. If you ping the FQDN of mensagens
also correctly resolve the IP address of the file server.
However, if I try to connect to \ \ Testro \ sharename I get the message
"\ \ Testro \ sharename
You were not connected because a duplicate name exists on the network. Go to
system control panel to change the computer name and try again "
I tried using different values CNAME and whatever I choose
yet this error. Can someone help me.
Have you mad the above registry change?
What version of Windows is your "Testro" server running?
I was looking for information on **** as I usually face problems in working on *****, so I am happy to find this post very useful for me. These kinds of posts are useful for anyone from beginner to the professional. Thanks for sharing
We have 2008R2 Fileserver and failed it over to our DR site. Long story short all Win7 Systesms worked fine, XP would get the error. Thanks to your instructions I got the issue resolved!
I am glad it helpded
thanks. It works!
Good day
I Have the same error as above, and it is really strange..it started all of a sudden.
Windows XP machines try to login to Domain and get "Duplicate Name exists on the Network", This is definelty not possible , as the machines have individual ID's, we then login anyway, using the correct credintials, and the profile starts up.
But now I cannot connect to any shared drives, it states "The resource is already in use", sort of the same errors as above..
I have read through the posts above and dont quite understand it.
The DNS / PDC is a Windows 2008 Server.
Thanks Shawn
Hi all ;
i have windows 2008 R2 i did apply this registry key and 2 command without any success still receive this error
Hi,
Please take a look at the comment I posted on the 03/27/2010 at 22:01, I believe on 2008 you have to perform an additional step and setup an SPN.
If you can confirm if that works I will update the post.
I hope that helps?
Phil
This looks absolutely perfect. All these tinny details are made with lot of background knowledge. I like it a lot. This was a useful post and I think it is rather easy to see from the other comments as well that this post is well written and useful
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