How to find where a connection is failing

Question

I have a website running a basic ASP.NET application that is mostly used from a single location, which is my client's office. The server is at a high-class datacenter.

Whenever I've been testing or using my application from outside their office I have consistently good connections but from their office the connection seems inconsistent. Sometimes requests just don't seem to make it to the server from the browser. I'm not familiar with the network hardware in the office, but they do have a T1 connection which should always be on.

I've tried ping and tracert and everything looks normal. When running Firebug during a failed request the request shows up in the log, then just sits there without showing it is sending any data, eventually it times out.

My question is, what tools can I use to diagnose this connection problem and start to narrow it down to a specific cause so I can fix it? Its an intermittent problem so a long running tool would probably make more sense, if there is any available.

Thanks for any help.

Answer 1

All of your standard ping and traceroute tools are probably your best bet. I'm not understanding though, where is the site located?

If you open command prompt, run ping -t aspwebsiteurl.domain <- will show if there is packet loss. From command prompt again, tracert aspwebsiteurl.domain <- will show you what route the packet is taking to get the site. May also show you if there is one particular hop that is giving you the hickup.

Answer 2

Is there a proxy between the office and the datacenter that could be causing issues?

Also you could try Wireshark to try to debug the problem in more detail.

Answer 3

Speed Test - Internet Network Connection Speed may be of some help with some links to test out the connection at the client's office to see how well it works.

Another question is how far away is the client and the datacenter? If one is in New York and the other in Los Angeles then the distance apart may be a factor. Also, have you examined any possible DNS issues?