We have setup a web server behind a NAT router which we have properly port forwarded the requests to our web server. We have already assigned a dynamic DNS for the WAN IP of the web server (that is the WAN IP of the router).

The problem is: we can access the web server we setup but other clients cannot access to that web server.

We verified that we are accessing the same IP address; therefore I think the problem is not the ISP DNS.

Secondly, we tried curl-ing the webserver, but there is no response in the client's computer.

Thirdly, we tried installing Browsec VPN extension to bypass any potential blocking of the ISP and it worked! Sadly, based on a thread: https://security.stackexchange.com/questions/64123/browsec-vpn-and-anonymizer It shouldn't be trusted for sensitive data.

Lastly, since we have access to the web server but other clients cannot access the web server, we tried following the thread's idea of setting up a reverse proxy web site in our area for them to gain access to the web server but it did not work.


We are already out of ideas as to what is the problem.

We also tried burp-ing the web server from our computer and the client's computer. In the former, after sending the initial GET request, there are many succeeding GET requests that followed while in the latter, there are no succeeding GET requests that followed.

Another observation was, in the client's computer: We gained access to the webserver using mobile data but failed with DSL connection; they are different ISPs.

How do we troubleshoot this problem?

  • Seems like a call to the client's ISP would be in order at this point. I think you've got enough evidence to ask for an explanation.
    – womble
    Sep 9 '15 at 6:08

Problem solved! Pretty ashamed that I made a mistake in setting up the reverse proxy server. The idea was actually positive.

Here was my analysis:

I tried sniffing the packets both in the client computer and reverse proxy server using wireshark and done the following observations:

Client -> reverse proxy server -> URL beautifier server -> web server

  1. Client connects to reverse proxy server.
  2. Reverse proxy server creates a request mapped from URI to URL beautifier server.
  3. URL beautifier server replies to reverse proxy server and forwards it to the client.
  4. The client gets a redirection HTML from URL Beautifier server and tries to connect directly to E-home server.
  5. Then we're back to square one where the client directly connects to the web server.

I should have set to create HTTP request to web server instead to the URL beautifier server. Anyways, it is now working. :D

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