C# Tracing Exception?

Question

1. I have developed a website using asp.net and c#.
2. I published that website using visual studio.
3. I gave that published website to my customers( more than 100).
4. My customers configured it in their own website.

I have handled exceptions using try catch and write log file in (c:\\Log\\Log.txt) with unique id and datetime. My problem is whenever any exception occurs for my clients, to solve the issue i need that log.txt file. But i have to wait till they provide log.txt file.

So , is there any way to read that exception using any code or any tool?.(now i cant modify my source because of customers currently running it).

For example: i give customer's URL in browser and performing some operations.Now i need a tool or code that should trace exceptions while i am accessing that website

Answer 1

After search in google i found that its not possible to trace exceptions on a website without modifying its code. Even using tools such as fiddler we can find only web requests and response.