I have an instance of Windows Server 2012 R2 running on Amazon Web Services. I am not able to make a TCP connection to the server on any port higher than 6000 for some reason. All ports below 6000 work, however. I've tested this with a short C# program that listens for TCP connections on the specified port and I've been initiating the connections with telnet. In an effort to eliminate possible causes, I've made sure the security group on AWS allows all incoming and outgoing traffic, and Windows Firewall is turned off.
Does anyone have any advice to help me troubleshoot?