Cannot connect to a port from outside even if Windows Firewall is OFF

Question

I'm getting a strange problem in my Windows 2008 R2 server running on a Hyper-V Virtual Machine. My application is listening to port 8002, which is well listed in command: netstat -na

Now I'm able to telnet to the same port (8002) from the same system, but I could not Telnet to this port from another system in the same VLAN. I'm able to Telnet port 135 of the server from another system, but not to this port (8002). I had turned off the Windows Firewall, enabled logging, allowed all traffic etc, but there was no sign of the connection from outside system.

Even I checked to Telnet to some other ports, and to my surporise, some of the connected but some didn't. Also, I run the same application in different system, it got connected from outside. Hence, I deduce that this is not the problem with the application. Please help.

EDIT: The system (both Windows 2008 r2 & Hyper-V) is a newly installed one.

RESOLVED: This issue is resolved, after we have found that, the antivirus client installed at the Hyper-V hypervisor (not the windows VM) is blocking the connection! Still don't know,why it is happening to this AV client only! Thanks to everyone!

Solution

You could check if the server is listening to the correct ip address (either the one you expect or 0.0.0.0).

When running netstat -an it will show you the local address.

Comments

[joeqwerty]

Try turning the firewall back on and creating an inbound rule for your port and try again.

[HopelessN00b]

Please don't add an answer to your question. We prefer that you add it as an answer, and accept it, to make it easier for any future readers. Self-answering id acceptable, and even encouraged around here.

[user177641]

I'm getting server is listening to the port (8002) of 0.0.0.0 and I can telnet to the port from the same system using: telnet <ipaddress> <port> But when i do the same from other systems in the VLAN, it is not getting connected!