This is the fifth part in the Apache Nifi configuration series. However, before you start with this guide, please be sure to have gone through the previous sections that explain:Installing Apache Nifi for Windows and Linux/macOSConfigure processors for Apache NiFiConfigure Controller servicesConfiguring Lingk GET and POST APIsIn this guide, we will configure the needed resources for our first Lingk on-premise integration recipe, and use the APIs we have configured to create a recipe for GET and POST requests.Firewall configurationBefore your Apache NiFi installation can communicate with the Lingk infrastructure, you need to make sure your routing/firewall configuration allows communication to the following Lingk IP addresses:Addresses for whitelisting35.169.101.6952.54.3.6554.221.31.21434.226.102.5535.170.25.3234.200.4.8144.198.107.22834.233.141.8552.20.84.104Opened portsStandard SSL port - 443API communication port - 3002Take note of the public address of your API (e.g. https://myhost.domain.com)If you are using a test environment, you can use ngrok or other tunnelling services to get a public DNS for your https://localhost:3002)Create your first Lingk Adapter connectorLogin to the Lingk dashboard at https://app.lingk.io.(Optional) Create an environment.In the connectors list in your environment, click "Add Source" to see the list of connectors you can add. Type "Lingk" in the search bar and click "Lingk Adapter"Enter your public API endpoint in the Data Source Endpoint field, then take click "Generate Adapter Secret"Go back to the Apache Nifi dashboard and double-click your process group to drill down to the child processors.Double-click the API credentials processor to show the processor properties.If you have an existing credential similar to client.secret.integration.testapp1:XXXXXXX matching the information in the Lingk connector you just created, edit that (like the below image). If you do not, go ahead and create a new property:value pair.Once you are done, click Apply to save  your changes.Navigate back to the root process group, click the process group, and click Start to start all the processors.All systems should be green once again.Now go back to the Lingk dashboard and click "Save and test Connection", and your connection should be successfully saved.In your connectors list, the Lingk Adapter connector status should also be green.In the next guide, we will be using these endpoints in a Lingk recipe to retrieve and add data to the database.