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Question
Thursday, May 16, 2019 10:06 AM
Hi everybody,
we have several serious problems with our DFS-N setup.
We got three DCs and a namespace called "dfs". Often, clients are unable to connect or losing connections. So I started investigating and found that using
dfsdiag /TestReferral /DFSPath:\xxxxx.xxx\dfs
is resulting in this error:
Checking the registry of the namespace servers...
Error: The system cannot find the file specified.
Warning: Unable to verify the registry of the following namespace server: "xxx"
This happens for two of the three servers, so I opened the registry on theses machines and looked under
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DFS\Roots\Domains
The result: On the two servers which are mentioned by dfsdiag, there is a subkey missing:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DFS\Roots\Domain\dfs
This contains on the one server "LogicalShare" and "RootShare" (REG_SZ) with the value "dfs".
Have I to add the subkey manually to the two other servers? How can this happen and is it possible that this is the source for our DFS problems?
Best regards!
All replies (23)
Wednesday, June 26, 2019 2:24 PM ✅Answered
Hi everyone,
finally I found the reason for all the problems.
On all thre servers the DFS namespace service is installed but only on one server there were the dfs root share present. So on \dc1\dfs existed but on \dc2 and \dc3 not while browsing them via explorer. Accessing \dc1\dfs, \dc2\dfs and \dc3\dfs worked but the shares were not visible on the two other servers!
After recreating the shares on the two servers pointing to c:\dfsroots\dfs now the problem seems to be solved. I found it weird that the dfsdiag tool do not remark this...
The shares must have been deleted by something or someone because the problems stared in may 2019.
Thanks for all attempts to help, perhaps someone can help this solution in the future.
Regards
Thursday, May 16, 2019 10:16 AM
Hello Marius,
The Windows registry should be identical for the DFS registry entries, you could try adding the same registry entries, however please make sure to backup the registry before doing any changes.
In addition, what is the result of the following command?
DFSDiag /TestSites /DFSPath:\\<domain name>\DFS /Recurse /Full
Best regards,
Leon
Blog: https://thesystemcenterblog.com LinkedIn:
Thursday, May 16, 2019 11:35 AM
Hi Leon,
thank you for your reply.
I added the missing keys and now the errors with dfsdiag /TestReferral are gone.
The results of /TestSites are all fine for our three DFS/DC servers, only our two fileservers, which are domain joined (NetApp) have an error that there is no sitename present.
Best regards,
Marius
Thursday, May 16, 2019 11:47 AM
Great to hear that, it seems that the referrals are OK now.
Can you provide the whole output of the /TestSites?
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Thursday, May 16, 2019 11:58 AM
Unfortunately, our servers are in german language.
So the whole output would be in german. Currently I try to add the english display language pack via dism but its stuck.
Thursday, May 16, 2019 3:15 PM
Great to hear that, it seems that the referrals are OK now.
Can you provide the whole output of the /TestSites?
Blog:
https://thesystemcenterblog.com LinkedIn:
Finally managed to install the english display language, here is the output. fs1 and fs2 are the NetApp Fileservers.
C:\Windows\system32>DFSDiag /TestSites /DFSPath:\fhg-ilt1.ilt.fraunhofer.de\DFS /Recurse /Full
Starting TestSites...
Error: The RPC server is unavailable.
Warning: Unable to gather domain info; ignoring server: null
Validating the site associations on every domain controller of the following: dc1
Success: The site associated with the following host name is consistent on all accessible domain controllers: dc1
Validating the static site association by accessing the registry.
Success: The static site-association of the following host name is consistent with the site-association in Active Directory Domain Services (AD DS): dc1
Validating the site associations on every domain controller of the following: dc2
Success: The site associated with the following host name is consistent on all accessible domain controllers: dc2
Validating the static site association by accessing the registry.
Success: The static site-association of the following host name is consistent with the site-association in Active Directory Domain Services (AD DS): dc2
Validating the site associations on every domain controller of the following: dc3
Success: The site associated with the following host name is consistent on all accessible domain controllers: dc3
Validating the static site association by accessing the registry.
Success: The static site-association of the following host name is consistent with the site-association in Active Directory Domain Services (AD DS): dc3
Validating the site associations on every domain controller of the following: fs1
Error: No site name is available for this machine.
Validating the static site association by accessing the registry.
Error: No site name is available for this machine.
Validating the site associations on every domain controller of the following: fs2
Error: No site name is available for this machine.
Validating the static site association by accessing the registry.
Error: No site name is available for this machine.
Finished TestSites.
Thursday, May 16, 2019 3:22 PM
"The RPC server is unavailable" is simply the firewall blocking the connection.
The fs1 and fs2 were NetApp boxes right? I think this is normal behavior, so in other words it looks good.
Blog: https://thesystemcenterblog.com LinkedIn:
Friday, May 17, 2019 7:36 AM
Hi,
Thank you for posting here.
Agree with Leon.
Also for your reference:
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
Best regards,
Lavilian
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Friday, May 17, 2019 9:18 AM
"The RPC server is unavailable" is simply the firewall blocking the connection.
The fs1 and fs2 were NetApp boxes right? I think this is normal behavior, so in other words it looks good.
Blog:
https://thesystemcenterblog.com LinkedIn:
Thanks for your answers.
Yes, as I wrote the fs1 and fs2 are NetApp fileservers.
Concerning the "RPC server is unavailable" message, on all of our internal servers the firewall is disabled.
But the problem still exists: Users are calling us because they can not use dfs mapped network drives, they are losing connection from time to time but not all are affected.
Friday, May 17, 2019 9:26 AM
The clients that are working and those that are not, are they connecting to the same DFS namespace member server?
Do you have multiple sites in use?
Blog: https://thesystemcenterblog.com LinkedIn:
Friday, May 17, 2019 10:40 AM
We do not have multiple sites, only one.
How can I check to which server the clients are connecting? Via dfsutil cache referral?
Friday, May 17, 2019 10:47 AM
Easiest is by copying the dfsutil.exe from the C:\Windows\System32 folder on the DFS server, to a client computer.
Then in a command prompt run:
Dfsutil.exe /PktInfo
You should get something like this:
As you can see in my screenshot above, the Namespace (\LAB\Test) has DC02.lab.ad that is the active Namespace member server ( ACTIVE TARGETSET ).
You can also view this by right-clicking the DFS shared folder, go to the DFS tab:
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Friday, May 17, 2019 11:08 AM
Next time, I get a client with problems, I will check which server is set to active.
On my workstation, what surprises me, is this output:
Entry: \domain\dfs
ShortEntry: \domain\dfs
Expires in 0 seconds
UseCount: 0 Type:0x81 ( REFERRAL_SVC DFS )
0:[\dc1\dfs] AccessStatus: 0xc00000cc ( TARGETSET )
1:[\dc3\dfs] AccessStatus: 0xc00000cc
2:[\dc2\dfs] AccessStatus: 0 ( ACTIVE )
Entry: \domain\sysvol
ShortEntry: \domain\sysvol
Expires in 0 seconds
UseCount: 0 Type:0x1 ( DFS )
0:[\dc1\sysvol] AccessStatus: 0 ( ACTIVE )
Entry: \domain.subdomain.de\dfs
ShortEntry: \domain.subdomain.de\dfs
Expires in 0 seconds
UseCount: 5 Type:0x81 ( REFERRAL_SVC DFS )
0:[\dc3\dfs] AccessStatus: 0xc00000cc ( TARGETSET )
1:[\dc2\dfs] AccessStatus: 0 ( ACTIVE )
2:[\dc1\dfs]
What about the error code "0xc00000cc"?
Friday, May 17, 2019 11:10 AM
You can view all the error codes over here:
2.2.2.4 SMB Error Classes and Codes
/en-us/openspecs/windows_protocols/ms-cifs/8f11e0f3-d545-46cc-97e6-f00569e3e1bc
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Friday, May 17, 2019 11:44 AM
Yes, I found that document but I do not understand the error.
"Invalid server name in Tree Connect." - when I try to access the path with this error ([\dc3\dfs] AccessStatus: 0xc00000cc) I have no problem accesing it. I then see all the content of the namespace...
Friday, May 17, 2019 11:59 AM
Basically the "tree connect" is for example this: \servername.domain.com\DFS
I suggest you open the DFS Management console, and then create a Diagnostics report, check what it says.
Blog: https://thesystemcenterblog.com LinkedIn:
Friday, May 17, 2019 12:39 PM
Well, the diagnostic report seems only available for DFS-R but we dont use this. We only use DFS-N.
Furthermore, opening \servername.domain.com\DFS works flawless for every single server ( \dc1.domain.de\dfs, \dc2.domain.de\dfs, \dc3.domain.de\dfs ...)
Friday, May 17, 2019 12:56 PM
Apologies that's right.
So all the DFS Namespace servers are responding as they should, have you also double checked the DNS for all servers that they also resolve correctly?
Since you added the Windows registry entries earlier, it could be good to reboot the DFS namespace member servers that had the registry entries added.
I suggest you monitor the situation closely, so the next time a client has problems connecting to a DFS namespace/share, check the event logs of the client PC during the time frame when the issue appeared, also check the event logs of the DFS server the client tried to connect to.
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Tuesday, May 21, 2019 6:52 AM
Hi,
Just checking in to see if the information Leon provided above was helpful. Please let us know if you would like further assistance.
Best Regards,
Lavilian
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Thursday, May 23, 2019 2:16 AM
Hi,
Just want to confirm the current situations.
Please feel free to let us know if you need further assistance.
Best Regards,
Lavilian
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Tuesday, June 4, 2019 1:36 PM
Hello,
sorry for my late resonse.
Yes, all servers are resolved correctly, even to their fqdn names.
In the meantime I had one case where I could live check via dfsutil. The clients network drives were not mapped during startup so I checked via dfsutil and got this:
ShortEntry: \dc2\dfs
Expires in 27 seconds
UseCount: 0 Type:0x81 ( REFERRAL_SVC DFS )
0:[\dc1\dfs] AccessStatus: 0xc000026d ( TARGETSET )
1:[\dc3\dfs] AccessStatus: 0xc000026d
2:[\dc2\dfs] AccessStatus: 0 ( ACTIVE )
0xc000026d seems to me not normal, but I can not find a lot about this, only that it means STATUS_DFS_UNAVAILABLE
At the same time I was able to connect from an other computer to the dfs, no matter which namespace server I tried. In the meantime also our linux computers have massive problems connecting to DFS shares so it does not seem to be a client problem.
Unfortunately there were no abnormalities in the system event log of the client.
Friday, June 7, 2019 7:57 AM
Hi，
Thank you for your reply.
This code means the DFS is unavailable on the contacted server. But I fail to find a workaround directly towards this error.
Here is an official article with similar situation for your reference:
Hope the resolution there can be a sally port.
Best Regards,
Lavilian
Please remember to mark the replies as answers if they help and unmark them if they provide no help.
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Thursday, June 27, 2019 8:31 AM
Hi,
I am glad to hear that your issue was successfully resolved.
Appreciate your sharing very much.
If there is anything else we can do for you, please feel free to
post in the forum.
Have a nice day!
Lavilian
Please remember to mark the replies as answers if they help and unmark them if they provide no help.
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