C4 here means PaaS (Platform as a service).
Up till now, the Snova proxy has already supported 6 C4s, which are Appfog, CloudFoundry, Dotcloud, Heroku, Jelastic and Openshift.
Regarding how to configure Snova for C4, you can check out the instructions in this post, but which was based on 0.15.0, and was a little out of date for the latest version 0.22.0, since “c4-client.conf” has been integrated into “sonva.conf”.
So, the following will make an update and show you how to configure C4 on the latest Snova (Java) client.