TCP/IP:

80 (Internet Radio, updates and registration)
443 (Rhapsody, Napster, and SiriusXM)
445 (CIFS)
3400 (incoming UPnP events - Sonos Controller App for Mac or PC)
3401 (Sonos Controller App for iOS)
3445 (OS X / Windows File Sharing)
3500 (Sonos Controller App for Android)
4070 (Spotify incoming events)
4444 (Sonos update process)
UDP:

136-139 (NetBIOS)
1900 (UPnP events and device detection)
1901 (UPnP responses)
2869, 10243, 10280-10284 (Windows Media Player NSS)
5353 (Spotify Control)
6969 (Initial configuration)
Note: When configuring a software firewall, the above ports will require inbound access.