LUA push Defs or SEPM Pull defs?

I need to open our firewall for LUA to communicate with SEPM server. We have LUA in the dmz that picks ups the updates which will distributed to SEPM server and the clients will pick up the defs from SEPM.

Our network team are asking If LUA pushes the DEFWS to SEPM or does SEPM pull the defs from LUA. I am still in the process of configuring LUA as SEPM server just got defs straight from web.