IIS logs questions

Question

I have few questions related to iis logs:

1)I have noticed many iis logs contain the same information but row are duplicated, why is it so?

2)For the same cookie in some rows Asp.net sessionID remain missing. For example if there are 5 rows for the same cookie then in the first 2 rows there is no Asp.net sessionid and for rest 3 everything is fine, why?

3)Is there any way through which i can find out the time spent by user in the last visited page. Reason being, we don't have any DateTime information after last visited page?

Answer 1

Question 1 IIS log mystery.

what you see as one page access is actually several accesses try and use Fiddler it will show you the connection steps.

EX:
I want page A -> no you need to authenticate     -> no sessionID
how can I authenticate -> you need to do this    -> no sessionID
here is my authentication -> here is page A.     -> sessionID is present.

Question 2 find out the time spent on page.

there is no reliable way of finding this you can approximate by sending some start message on page load and one adder on page leave (but you are depending on client code and you never trust on client code).

Answer 2

1. If you have several requests to the same page at the same time, and browsers are the same, it will look like you have duplicated rows (it's just more than 1 user hitting the page at once). If the IPs are the same, it's most likely a handshake, as Pedro.The.Kid pointed out, or you may have some very strangely behaving code.

2. See ASP.NET_SessionId is missing

3. You might be able to track this in your application code. Do you want to track it in your application or through your IIS log? Also, what exactly are you trying to do with that information? Google Analytics will be able to give you approximate page view times and other information.