One annoying feature in modern Ubuntu distributions.

// Return false if the local machine's DNS hostname is bad, also pop up an
// error dialog.  Return true if the name is OK.  A bad name is one we believe
// will have problems being registered in DNS after a promotion.  The user
// must fix a bad name before proceeding.
 
bool
IsComputerNameOk()
{
   LOG_FUNCTION(IsComputerNameOk);
 
   bool result = true;
 
   do
   {
      State::RunContext context = State::GetInstance().GetRunContext();
      if (
            context == State::BDC_UPGRADE
         || context == State::PDC_UPGRADE
         || context == State::NT5_DC
         || !IsTcpIpInstalled() )
      {
         // If the machine is already a DC, then we don't worry about the name.
         // 
         // If the machine is a downlevel DC undergoing upgrade, then the name
         // can't be changed until dcpromo is complete.  So, we say nothing now,
         // but remind the user to rename the machine in the Finish Page.
         //
         // If TCP/IP is not installed, then the machine has no hostname
         // to check.  In this case, we will check for that with the
         // InstallTcpIpPage
 
         ASSERT(result == true);
 
         break;
      }
 
      // Then check the computer name to ensure that it can be registered in
      // DNS.
 
      String hostname =
         Win::GetComputerNameEx(::ComputerNamePhysicalDnsHostname);
 
      DNS_STATUS status =
         MyDnsValidateName(hostname, ::DnsNameHostnameLabel);
 
      switch (status)
      {
         case DNS_ERROR_NON_RFC_NAME:
         {
            INT_PTR dlgResult = 
               NonRfcComputerNameDialog(hostname).ModalExecute(0);
 
            switch (dlgResult)
            {
               case NonRfcComputerNameDialog::CONTINUE:
               {
                  // continue on with the non-rfc name
 
                  ASSERT(result == true);
 
                  break;
               }
               default:
               {
                  // close the wizard and rename.
 
                  result = false;
 
                  // after calling this, we must not allow any promote
                  // operation.  We will fall out of this function, then
                  // end the app.
 
                  LaunchNetId();
                  break;
               }
            }
 
            break;
         }
         case DNS_ERROR_NUMERIC_NAME:
         {
            result = false;
 
            String message =
               String::format(
                  IDS_COMPUTER_NAME_IS_NUMERIC,
                  hostname.c_str());
 
            BadComputerNameDialog(message).ModalExecute(0);
 
            break;
         }
         case DNS_ERROR_INVALID_NAME_CHAR:
         case ERROR_INVALID_NAME:
         {
            result = false;
 
            String message =
               String::format(
                  IDS_COMPUTER_NAME_HAS_BAD_CHARS,
                  hostname.c_str());
 
            BadComputerNameDialog(message).ModalExecute(0);
 
            break;
         }
         case ERROR_SUCCESS:
         default:
         {
 
            break;
         }
      }
   }
   while (0);
 
   LOG(result ? L"true" : L"false");
 
   return result;
}