According to http://www.antirez.com/news/96 http://www.antirez.com/news/96 it binds to 0.0.0.0 by default, though in latest versions there is an example config

According to http://www.antirez.com/news/96 http://www.antirez.com/news/96 it binds to 0.0.0.0 by default, though in latest versions there is an example config file provided for binding to 127.0.0.1