@mkshaji see server.cfg:
# Enable or disable clipboard:
#
# client: The content copied on the client can be pasted inside the
# NX session.
#
# server: The content copied inside the NX session can be pasted
# on the client.
#
# both: The copy&paste operations are allowed between both the
# client and the NX session and viceversa.
#
# none: The copy&paste operations between the client and the NX
# session are never allowed.
#
#EnableClipboard both