If you are behind a firewall, you can define the proxy settings in the global options section:

<curiosity>
  <options>
    ...
    <proxy>
        <host>proxy.example.com</host>
        <port>8080</port>
        <user>theUser</user>
        <pwd>5WFEvFwgbOFMRpwZB=</pwd>
    </proxy>
  </options>
  ...
</curiosity>

Don't forget to encode the password as explained here.

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