Security

By default, Rack::Bug will only allow ‘127.0.0.1’ to connect. To enable other IPs, you need to provide a different IP mask in the options.

To enable SQL query running/profiling, Rack::Bug requires that you set the secret key.

And, finally, it’s tremendously good practice to set a good password if you’re not running Rack::Bug from localhost.

So, here’s all of them:
config.middleware.use "Rack::Bug", :ip_masks => [IPAddr.new("127.0.0.1"), IPAddr.new("my.ip.as_seen.from_server")], :secret_key => "RgXEMzQVJkZ5YKL8YKhO5EXR3EkrXtoJyUekAVB4ceAbccRGEO+uCLN0G88gB/e/g83u9ojvZv1daWE5pBAvjg==", :password => "rack-bug-secret"

You can easily generate a secure random number of any length using ActiveSupport::SecureRandom:

ActiveSupport::SecureRandom.base64(64) # 64-char base64-encoded secret key

(Pulled from http://www.themomorohoax.com/2009/04/20/debugging-rails-2-3-2-apps-with-rack-bug, many thanks!)