You will need to verify that the server has been enabled for file share access using the cname/alias.
By default windows 2003/2008/2008R2 does not allow file share access by cname/alias.
To allow access to the file share using the alias, the following registry entries are required.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters
add a value DisableStrictNameChecking of type DWORD set to 1.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0
add new Multi-String Value BackConnectionHostNames
Enter the FQDN of the CNAME.
Optionally to provide a netbios alias access also:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters and add a value OptionalNames of type Multi-String
Add the netbios alias for the server.
The server will need to be rebooted after these are applied.
Verify you can navigate to the file share using the alias name.
You will then need to add a host file entry for the alias to the IP address of the server.
Edit the following file in a text viewer (e.g. notepad):
C:\windows\system32\drivers\etc\hosts
You need to enter the IP address to the FQDN for the cname
e.g.
10.20.30.100 filealias.domain.com
Save the file and enter the alias into the storage options for a network share backup.
The alias name will now be used to backup and stored accordingly in the configuration database.
