You must properly configure out-of-band capable computers to be able to connect to those computers using the out-of-band management technologies.
For more information, see http://www.symantec.com/docs/DOC6628
To work with Intel AMT, ASF, DASH, IPMI, you must enable and configure the technology in the target computer's BIOS manually. Or you can remotely configure client computer, using specific software provided by vendors. Refer to the hardware manufacturer's documentation.
For Intel AMT support, use Intel AMT Configuration utilities, that are available for download from Intel.