Thank you again ,Vitaliy .

 d $system.OBJ.DisplayError(##class(%Net.Remote.Utility).RunCommandViaCPIPE("getmac /NH /fo table",,.result))
 w $p(result," ",1)

this method might be return the server physical address.If I use this method on my  pc (PC as server),it return ture physical address.

Thank you Vitaliy,but just as Danny say,it is the same as 'write $SYSTEM.INetInfo.EthernetAddress(0)',and in cache 2010 I can not use '

w $$$DEFETHADDR

'