trace a particular IP and port

I have an app running on port 9100 on a remote server serving http pages. After I ssh into the server I can curl localhost 9100 and I receive the response. However I am unable to access the same app from the browser using `http://ip:9100` I am also unable to telnet from my local PC. How do I debug it? Is there a way to traceroute a particular IP and port combination, to see where it is being blocked? Any linux tools / commands / utilities will be appreciated. Thanks, Murtaza