Out of the box, RSAT for Windows 10 does not include DNS tools.

#Official instructions from Microsoft
https://support.microsoft.com/en-us/help/4055558/rsat-missing-dns-server-tool-in-windows-10-version-1709

#RSAT Win10 installer download
https://www.microsoft.com/en-gb/download/details.aspx?id=45520

NOTE: RSAT Win10 cannot already be installed for the below to work. Uninstall first if it has been installed

Win10 RSAT KB: KB2693643

x64 Install

1. Download the Windows 10 RSAT installation package, if not already downloaded.

2. Create \temp directory somewhere, and create these two files within the directory

#unattend_x64.xml

<?xml version="1.0" encoding="UTF-8"?>  
<unattend xmlns="urn:schemas-microsoft-com:setup" description="Auto unattend" author="pkgmgr.exe">  
  <servicing>  
    <package action="stage">  
      <assemblyIdentity buildType="release" language="neutral" name="Microsoft-Windows-RemoteServerAdministrationTools-Client-Package-TopLevel" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" version="10.0.16299.2"/>  
      <source location="." permanence="temporary"/>  
    </package>  
  </servicing>  
</unattend>

#installx64.bat

@echo off
md ex
expand -f:* WindowsTH-RSAT_WS_1709-x64.msu ex\
cd ex
md ex
copy ..\unattend_x64.xml  ex\
expand -f:* WindowsTH-KB2693643-x64.cab ex\
cd ex
dism /online /apply-unattend="unattend_x64.xml"
cd ..\
dism /online /Add-Package /PackagePath:"WindowsTH-KB2693643-x64.cab"
cd ..\
rmdir ex /s /q

3. Copy the Windows 10 RSAT installer package into the \temp directory

4. Open cmd.exe as an administrator and run the batch file you created above.

installx64.bat

NOTE: This takes several minutes to install.

5. Reboot when prompted