Can't access ports assigned to Rails 4.2, but 4.04 works fine
Solution 1:
WEBrick bound to 127.0.0.1 rather than to INADDR_ANY, so you can only access it via that address. If you want to set what address it binds to, use the -b option. For example:
rails s -b 0.0.0.0 -p 3004