virtualbox.org

When I select Help>Check for Updates or Help>Register Virtual box I get the error:

connect(): No route to host

I must use a proxy to connect to the interet. How can I configure a proxy in Virtualbox?

I suggest you put the proxy in your general settings. E.g. if you use the command line to update your distro, it should use the system defined proxy server. VB should act the same way.

For the updates, you can check manually every once in a while by visiting the website.