Analyst's Notebook Connector for Esri is able to connect to any ArcGIS server. Your organization might use servers that are owned and maintained by Esri; public-facing map servers; or your own maps on a server within your organization. You might use a combination of all of these servers.
When you start Analyst's Notebook and Analyst's Notebook Connector for Esri is installed, some servers might connect immediately. You can connect to others as required.