Este verificará si ya tiene las DNS nuevas, en caso contrario, las cambiará.
On Error Resume Next
strComputer = "."
strDNSNuevas = "Servidor_DNS_1,Servidor_DNS_2″
Set objWMIService = GetObject("winmgmts://" _ & "{impersonationlevel=impersonate}|\" & strComputer & "rootcimv2″)
Set colNetCards = objWMIService.ExecQuery _ ("SELECT * FROM Win32_NetworkAdapterConfiguration WHERE IpEnabled = True")
For Each objNetCard In colNetCards
strDNSs = Join(objNetCard..DNSServerSearchOrder,",")
If strDNSs <> strDNSNuevas Then
objNetCard.Set.DNSServerSearchOrder(Join(strDNSNuevas,","))
End If
Next