I know this is an old thread but I just thought I would add something for anyone coming through and reading. DO NOT USE PORT 80! That is a port specifically used for http communication *a web server / browser usually* and quite a few ISPs are now blocking port 80 for connections not initiated by your IP address because they see that as you running a webserver from home which normally violates the ToS. When setting up Subsonic you should use a port number that isn't a common number, ie, above 1024. Also be warry of any editing of your hosts files. Just do it the right way and forward the port in your router. In 99% of cases you won't have to mess with adding an exception to windows firewall.
If you access your home PC from outside then you really should have a router between your network and your cable/DSL modem for security. Open ports can be a serious security risk.
https://www.grc.com/x/ne.dll?bh0bkyd2