Presently, the getBaseUrl function within SONOSHelper disregards the protocol and port from the redirect URL when building the SOAP responses to SONOS players outside the network. It forces the media items to be accessed via http, and always on the port that Subsonic is running (resulting in http requests on 443, for example). The current workaround (pass the ip as a string in the endpoint URL, e.g. Sonos?ip=SUBSONIC_IP) is attempting to solve a problem that is already solved satisfactorily by the rest of Subsonic (M3UController, PodcastController, NowPlayingService, etc.)
Per the SONOS documentation
http://musicpartners.sonos.com/node/339,
As more private data migrates online, services that handle this data have to consider enabling stronger security protocols. Therefore, Sonos requires that you implement the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) security requirements listed below in your Sonos Music API (SMAPI) implementation.
