HttpWebRequest "keep-alive" header gets dropped - firefox

Question

I am in NTLM hell here, hope you can help indentify what I am missing.
I am ultimately trying to deliver SSRS reports to a frame in a browser, and only the images within the reports are giving me much grief. They don't appear unless the user has Firefox and enters their credentials 2 times, first for the report, then a second time for the images in the report.
I am using HttpWebRequest to obtain the SSRS reports.
I am sending the webserver (IIS 7.5) a credential cache with "NTLM" and valid credentials to try and obtain an images from SSRS after I receive the HTML stream so that I can store them locally and refer to those, which would alleviate the users from having to re-enter credentials again and again.
I see in Fiddler that Type 1, 2 and 3 challenges are properly met during the NTLM hand shaking, however, the final response is 500 internal service error. The response text also indicates rsStreamNotFound, however, I find next to no info on what that means and I think it's misleading as to what the real problem may be.
When I use Firefox, Firefox prompts me for my network credentials for the report and then again for the images, and it gets through bringing the images back. My HttpWebRequest fails with 500 Internal Server Error, and rsStreamNotFound.
The only difference I can see in the request headers between Firefox requests and my requests is that the "keep-alive" property gets dropped from my programmatic request, and the Firefox requests have it in there.
Why do my "keep-alive" get dropped?
At this point, that is the only difference between my request and the request from Firefox, so I would like to eliminate that difference before jumping to any other conclusion.
I tried variations of:
req.KeepAlive = true;
req.PreAuthenticate = true;
and this gem:
var sp = req.ServicePoint;
var prop = sp.GetType().GetProperty( "HttpBehaviour", BindingFlags.Instance | BindingFlags.NonPublic );
prop.SetValue( sp, (byte)0, null );
Here is the CredentialCache:
CredentialCache credentialCache = new CredentialCache();
credentialCache.Add( new Uri( path ), "NTLM", NetCredentials );
... and "keep-alive" is not present in the request for my HttpWebRequest, and Firefox has it - why does mine get dropped?
Update:
I tried:
using (WebClient client = new WebClient()) {
client.DownloadFile(url, filePath);
}
...and I got 401 Unauthorized, so I tried with credentials and get 500 Internal Server Error

Answer 1

It is not clear from your question where you are running the code. Is it running on the desktop as an executable? Or is it running inside firefox as some sort of activex control or something similar?
Anyway, I suggest using .net tracelog facility to get a log of your transaction, and look at the logfile.
<?xml version="1.0" encoding="UTF-8" ?>
<configuration>
<system.diagnostics>
<trace autoflush="true" />
<sources>
<source name="System.Net">
<listeners>
<add name="System.Net"/>
</listeners>
</source>
<source name="System.Net.Sockets">
<listeners>
<add name="System.Net"/>
</listeners>
</source>
<source name="System.Net.Cache">
<listeners>
<add name="System.Net"/>
</listeners>
</source>
</sources>
<sharedListeners>
<add
name="System.Net"
type="System.Diagnostics.TextWriterTraceListener"
initializeData="System.Net.trace.log"
/>
</sharedListeners>
<switches>
<add name="System.Net" value="Verbose" />
<add name="System.Net.Sockets" value="Verbose" />
<add name="System.Net.Cache" value="Verbose" />
</switches>
</system.diagnostics>
</configuration>
If your app name is app.exe, create a file called app.exe.config in the same directory as the exe, and put the above contents into it. Then run the app, and a logfile should be created.
This link should have more information on getting logfiles, in case you have a problem.
creating a system.net trace log
You can put the logfile on pastebin after deleting personal information like hostnames, ipaddresses etc.
Also, give us a snippet of code that reproduces the problem. Then it will be easier to help.