"Out of the box" Nosto Digital Screens do not run through a proxy and all social content is stored on the original social network. As such to work, you will need to whitelist both Nosto's Digital Screen domain, plus each of the source networks you will be displaying content from.
If your business requires your Digital Screen to come through a proxy (i.e. you are not comfortable whitelisting social sites), please contact your Customer Success Manager for scoping and quotes.
For any further questions or queries, please send an email to support@nosto.com and our support team will get back to you.