| Application / Service | Typical Use Case | | :--- | :--- | | | Default Web Site, WSUS, or any internal web app. | | Microsoft SQL Server Reporting Services (SSRS) | Uses HTTP.SYS to listen on Port 443 for reports. | | Skype for Business / Teams | Can bind to ports unexpectedly. | | Remote Desktop Gateway (RD Gateway) | Uses HTTPS (443) for secure RDP connections. | | Syslog / SIEM agents | Some agents redirect SSL traffic via 443. | | Antivirus Web Filtering | Symantec, McAfee, or Cisco AMP can proxy HTTPS. | | Hyper-V Host Service | Certain Hyper-V configurations use port 443 for management. | | Docker Desktop (Windows containers) | The MobyLinuxVM engine may bind to 443. | | Previous Veeam Installation | Leftover services from a failed uninstall. |
To check and remove this listener: