What is a recommended capability to make an unauthenticated co-premise web application accessible within Salesforce?

Creating a Custom Web tab is a recommended capability for making an unauthenticated co-premise web application accessible within Salesforce. This approach allows you to embed a web-based application directly within the Salesforce interface, providing a seamless user experience.

Using a Custom Web tab enables you to specify a URL that points to the co-premise application, even if it is not secured by authentication. This method simplifies access for users who may not have individual credentials for the external application while still delivering relevant information and functionality directly within Salesforce.

The advantage of this method lies in its straightforwardness, as it allows quick access to web applications without the complexity of additional coding or configurations that might be required with other options. It promotes user accessibility and enables Salesforce administrators to manage the visibility of these tabs according to their business needs.

In contrast, while options like Visualforce pages and Apex callouts offer useful functionalities within Salesforce, they would either require more complex implementations or not be suitable for direct unauthenticated access. Lightning Connect, similarly, is designed for integration with external data sources but focuses on authenticated use cases rather than unauthenticated web applications.