to Yes, and set /UseDhcpPorts to No. The default is No. /RpcPort: Specifies the TCP port to use to service client requests. ...

to Yes, and set /UseDhcpPorts to No.
                                        The default is No.
[/RpcPort:]                Specifies the TCP port to use to
                                        service client requests.
[/PxePromptPolicy                       Configures how known (prestaged) and
                                        new clients initiate a PXE boot.
 [/Known:{OptIn|OptOut|NoPrompt}]       Sets the policy for prestaged clients.
 [/New:{OptIn|OptOut|NoPrompt}]         Sets the policy for new clients.
                                        OptIn means the client needs to
                                        press a key in order to PXE boot,
                                        otherwise it will fall back to the
                                        next boot device. NoPrompt means
                                        the client will always PXE Boot.
                                        OptOut means the client will PXE boot
                                        unless the Esc key is pressed.
[/BootProgram:]          Sets the default boot program for
                                        a given architecture. This is the
                                        path relative to the RemoteInstall
                                        share. For example:
                                        "boot\x86\pxeboot.n12".
 /Architecture:{x86 | ia64 | x64}       The architecture of the boot program.
[/N12BootProgram:]       The relative path to the boot program
                                        that does not require F12 to be
                                        pressed in order toPXE boot. For
                                        example: "boot\x86\pxeboot.n12"
 /Architecture:{x86 | ia64 | x64}       The architecture of the boot program.
[/BootImage:]            The relative path to the boot image
                                        that booting clients should receive.
 /Architecture:{x86 | ia64 | x64}       The architecture for boot image.
[/PreferredDC:]                The name of the domain controller that
                                        WDS should use. This can be
                                        either the FQDN or NetBIOS name
[/PreferredGC:]                Name of the global catalog server
                                        that WDS should use. This can be
                                        either the FQDN or the NetBIOS name.
[/PrestageUsingMAC:{Yes | No}]          Specifies whether WDS, when creating
                                        computer accounts in Active Directory,
                                        should use the MAC address
                                        rather than the GUID as the
                                        identifier for the computer.