Problem Definition: 

I changed the subnet mask of my DHCP server from /16 to /24. When systems weren't responding, I changed it back to /16. Though a correlation is highly unlikely, this resulted in my users being unable to simultaneously login to multiple devices as they were able to in the past? I am getting the following error messages:


1. "The system could not flog you on due to the following error: The specific domain eithre does not exist or could not be contacted"

2. "Logon Unsuccessful:

The user name you typed is the same as the user name you logged in with. That user name has already been tried. A domain controller cannot be found to verify that user name."

Please help!

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Community Chosen Answer


I doubt it is a user name problem, you probaly need to flush dns  and release and renew the adaptor on the workstations that were on when you were making the mask changes.  Or shut them down and let them time out overnight.

Answered 12/20/2012 by: SMal.tmcc
Red Belt

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Do you authenticate with ldap, maybe a server outside the network now? Seems much more likely to be a network issue as smal says. 

Is the domain controller reachable now? 


Answered 12/20/2012 by: jdornan
Red Belt

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This could also be an inconsistently in the network the Domain Controller is on the what the endpoint is on.  Be certain the netmask the DHCP server is handing out to endpoints is correct.  If an endpoint is on a different network (meaning the first part of the netmask) is incorrect, it may not be able to communicate properly with the DC, either because both are on the same segment but have mispatched masks, or because the endpoint cannot properly communicate with its gateway to route traffic to and form the DC.

Answered 01/19/2013 by: mdri
Blue Belt

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