Yes Mr_miyagi If the port used by Symantec in the IIS ( by default 8014) is opned and the windows defender is turned off on the client then IDEALLY there should be no commuincation issues.
I am saying this from my Expreince of working with SEP for last 2 years.
In SEP the Client commuincates with the SEPM on the IIS port ( 8014). All the policy and updates are passed from the SEPM to client on this port. And the clients then upload their logs using the same port.
SO ,, If there is nothing that is blocking the port 8014 then there will be no commuincation issues irrespective of the OS.
If the SEPM is on 2003 and Client on XP and the port is blocked then the client will not commuincate with SEPM.
So in simple words for Comuincation the ports need to be opened , irrespective of the OS being used.
Hope this answers your question and clarifies your doubt