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

You can use the default traceroute command for this purpose, then there will be nothing to install.

traceroute -T -p 9100 <IP address/hostname>

The -T argument is required so that the TCP protocol is used instead of UDP.

In the rare case when traceroute isn't available, you can also use ncat.

nc -Czvw 5 <IP address/hostname> 9100