Plex server keeps NAS awake

Hi, I have the DL2100 and the EX2100 and installed the Plex Media Server on them (updated to current version). I have noticed that when the server on is but not actively streaming a movie, the system will not go to sleep…Is this normal? Is the server port for Plex always active and there by keeping the DL2100 awake?

Thanks in advance,

If there is a request from your network pinging DLNA servers then it may keep your unit awake.