Thanks; I too, need to now be on the same local network.
I too have 3rd Gen Apple TV which worked fine then randomly began having this issue. I do not have any firewall or alike software and normally a simple reboot usually help; in this case failed! I configured DHCP reservations for Apple Ethernet & WiFi connections via my wireless router, manually assigned the addresses in Apple TV Network preferences, restarted the Apple TV device, I'm now able to use home sharing via WiFi but ethernet not ethernet. To troubleshoot the home sharing via ethernet connection, I disabled my IMBP WiFi Card, connected both MBP and Apple TV to my router using ethernet cables then confirmed home sharing worked. Additionally, based on the Apple's TCP/UPD chart and using Terminal, Activity Monitor, and Network Utility I was able to verify daap uses 3689 (iTunes Sharing) and not as 5353 (Bonjour, AirPlay, Home Sharing, Printer Discovery, Back to My Mac) as the chart recommends.
Being on different networks in the past I had no issues or who knows, perhaps overlooked. What caused it? OSX update? iTunes bug? not sure.
Conclusion: Both devices (Apple TV + iPhone, iPad, MacBook) should be on the same netowrk (Wired or Wirelessly) and should work just fine.
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp4 0 0 machinename..daap 192.168.1.11.49270 ESTABLISHED
tcp4 0 303104 machinename..daap 192.168.1.11.49269 ESTABLISHED
tcp4 0 0 machinename..daap 192.168.1.11.49266 ESTABLISHED
tcp4 0 0 machinename..daap 192.168.1.11.49258 ESTABLISHED
tcp4 0 0 machinename..daap 192.168.1.11.49257 ESTABLISHED
Listen/Show for connections via terminal
machinename:~ username$ sudo lsof -i -P | grep -i "listen"
launchd 1 root 28u IPv6 0x57aeb7c59531c517 0t0 TCP localhost:631 (LISTEN)
launchd 1 root 29u IPv4 0x57aeb7c5953224ff 0t0 TCP localhost:631 (LISTEN)
vpnagentd 60 root 14u IPv4 0x57aeb7c595321dc7 0t0 TCP localhost:29754 (LISTEN)
iTunes 952 username 25u IPv4 0x57aeb7c59a6ddf57 0t0 TCP *:3689(LISTEN)
iTunes 952 username 26u IPv6 0x57aeb7c59531c137 0t0 TCP *:3689(LISTEN)
Message was edited by: WizeWun