I have an application running on Windows.
The application listens on port 54000.
I can connect to the application from the local machine and it works fine:
telnet 127.0.0.1 54000
Now, I am trying to connect to this application from remote. I started by adding Inbound Rules for the application, then for the port, finally I disabled Firewall for a private network (I made sure my network is set to private) because none of the above worked.
When I try to connect with telnet from remote I get:
telnet 192.168.1.227 54000 Connecting To 192.168.1.227...Could not open connection to the host, on port 54000: Connect failed
When I try to ping it, the ping succeeds.
On the local machine I check if the port is open, to be sure:
PS C:\Windows\system32> Get-Process -Id (Get-NetTCPConnection -LocalPort 54000).OwningProcess Handles NPM(K) PM(K) WS(K) CPU(s) Id SI ProcessName ------- ------ ----- ----- ------ -- -- ----------- 921 52 125336 120816 7.47 7008 1 myApp
I downloaded Wireshark on the local machine to see what is going on.
9345 141.851696 192.168.1.93 192.168.1.227 TCP 62 65153 → 54000 [SYN] Seq=0 Win=64240 Len=0 MSS=1460 SACK_PERM=1 9346 141.851793 192.168.1.227 192.168.1.93 TCP 54 54000 → 65153 [RST, ACK] Seq=1 Ack=1 Win=0 Len=0
As you can see the response is TCP RST which means that the application or the system does not want to talk.
I wonder who sends TCP RST the system or the application?
Can it be that the problem is with the application itself? For example, it can answer to localhost but not others?
Any ideas on how I can investigate this issue more?