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Using DNS Aliases on Windows Machines.

by @ 2:01 pm on 12/18/2009. Filed under tech

I regularly get asked about people adding CNAMEs to DNS to set up an alias for a Windows machine. Like maybe the machine name is server123site5 and they want to call it oldserver1. They do that and all of a sudden when they try to use it the connection attempt results in a “duplicate name exists on the network” error.


Not going to spend the time explaining why this happens other than it is a name validation in the SMB 1.0 handshake but the solution is to use either the DisableStrictNameChecking or OptionalNames registry keys under HKLM\Services\LanmanServer\Parameters.

See for more info.


Note that Windows 2008 and newer Server OSes and Windows Vista and newer Client OSes can use SMB 2.0 which doesn’t have this issue.



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