What is the purpose of port 80 in Qlik Sense?

The purpose of port 80 in Qlik Sense is indeed tied to its role as an optional listen port for the Qlik Sense Proxy Service using HTTP. The Qlik Sense Proxy Service is responsible for managing all client requests and routing them correctly to the appropriate resources within the Qlik Sense environment. While the default configuration for the Proxy Service often uses port 443 for secure HTTPS connections, port 80 can be utilized to allow for unencrypted HTTP traffic. This flexibility can be significant in environments where clients may connect without the need for the security provided by HTTPS, although it is generally recommended to use secure connections when possible.

Using port 80 is an optional choice; organizations can configure their Qlik Sense deployments as they see fit, including the choice of communication protocols and ports based on their security policies and infrastructure setups. Thus, recognizing and understanding the role of port 80 as an optional listen port reinforces the system's adaptability in various deployment scenarios.