Has anyone been able to successfully get casting to work from the Plex app (or any others) on say Android to a Roku device that's on a different subnet? I've been able to get this working with Chromecasts being they use mDNS but it doesn't look like the Roku's do. Trying to determine what protocol and ports the Roku uses to be found as a casting device in order to configure my network to route it between subnets.
Were you ever able to successfully resolve this issue, @JimPhreak sir? I'm in a similar situation, using an Edgerouter paired with a UniFi access point and unfortunately struggling with identical issues. Chromecast works after enabling mDNS within my cloud hosted UniFi Controller, however I'm not able to use the Roku remote app on my android phone after segmenting things off onto their own VLAN. YouTube streaming to the TCL55P607 Roku television still seems to work... could I potentially be missing some important firewall rule, or what else could it be? I'm not even certain what port the Roku remote app would want to work on... obviously I'm far from an expert. Sorry to revive an ancient thread, just wondering if any conclusion was ultimately reached. Thank you kindly for your time.