Plex on AppleTV Keeps Waking Up My iMac?

hi there,

whenever i watch a movie from abroad, i wake my mac (which runs PMS) via ssh and send it back to sleep after use. however, it never sleeps more than an hour before something wakes it up again.

according to syslog |grep -i "Wake reason" plex.app on my appletv consistingly seems to be the culprit:

Apr  9 09:40:58 myImac kernel[0] <Notice>: Wake reason: GIGE (Network)
Apr  9 09:40:58 myImac kernel[0] <Notice>: AppleBCM5701Ethernet [en0]: Wake reason: Enet.Service - Connection attempt with TCP from [ATV_MAC] [ATV_IP].61547 to [IMAC_IP].32400

where [ATV_MAC] is the MAC address of my AppleTV and [ATV/IMAC_IP] are the respective machine's LAN IPs.

what does my appletv want from my plex server? and how can i stop it?