I have an intranet ASP.NET 2.0 web app running on a Win 2003 SP2 server running IIS 6.0 that gives intermittent and, as yet, un-reproduceable username/password prompts for some of our users. I'm using authentication mode="Windows" in my ASP.NET app and Integrated Windows authentication in IIS, with "Enable anonymous access" unchecked. This should allow users on the local network to access the application without having to log in, by virtue of already being logged into the Windows local network. And this is exactly how it behaves most of the time. I use the application on and off throughout the day and have never experienced the problem on my own PC. I am based at our company's head office, where the servers and domain controllers are also based. Most users are based off-site but logged into the domain via an MPLS cloud lease line. Several users have reported seeing a username/password pop-up prompt during the course of their use of the application, but not necessarily at initial logon or even after a significant time away from the browser. They seem to see this once or twice a day, whilst using the app for most of their day. All browsers are IE 6. Because it is un-reproduceable it's very hard to work out which part of the architecture is causing the problem, but after a lot of research here are a few observations:
- <div mce_keep="true">The prompt box says "Connect to servername.domain.co.uk" in the title bar, but "Connecting to websitename.domain.co.uk" in the message prompt. Users are browsing websitename.domain.co.uk. The user name field is blank.</div>
- <div mce_keep="true">It seems to be caused by different objects at different times even for the same user. E.g. it could be an aspx page one time, then a gif the next time. You can tell because if you click "Cancel", the relevant gif doesn't appear. If you click "Cancel", then refresh, it browses fine without the need to submit a username/password, but most users seem to click "Cancel", close the browser, re-open it and carry on as if nothing had happened.</div>
- <div mce_keep="true">There is nothing unexpected in the PC event logs for users when this is happening.</div>
- <div mce_keep="true">There is nothing unexpected in the webserver event logs at times when this is happening</div>
- <div mce_keep="true">There is nothing unexpected in the web server IIS log at times when this is happening</div>
- <div mce_keep="true">The problem is happening to users with laptops and desktops alike, some wired, some wireless.</div>
- <div mce_keep="true"> <div>I borrowed a laptop from a user who experiences this problem and logged into it using my own network login in my own office (at head office) and experienced the prompt 2 or 3 times during a day of testing</div></div>
- <div mce_keep="true"> <div>I set up an identical laptop model with a disc image from the laptop in the previous observation. I am logged into this laptop as the problem user but in my own office. I cannot get the prompt to appear. I could not get it to appear when logged in as myself (supposedly an identical scenario to the previous observation) either.</div></div>
- <div mce_keep="true"> <div>There is a user on the head office network who does experience the prompt from time to time on her wirelessly linked laptop. I cannot see any difference in the settings for her IE when compared to mine.</div></div>
<authentication mode="Windows"/><authorization><deny users="?"/><deny roles="DenyGroup"/><allow roles="AllowGroup"/><deny users="*"/></authorization><identity impersonate="false"/><div>
My biggest problem is not being able to reliably reproduce the problem. Apart from that, I am also struggling to see anything in logs that might tell me what's going on. I guess I need to start logging at a more granular level (packet sniffing?). Can anyone please tell me what would be sensible thing to start logging and what to look for in those logs? Then the next time a user is able to report an occurrence of the prompt, I can dive into these logs and hopefully see something useful.
Otherwise, has anyone seen anything similar, or have any ideas what is causing this? I can't find a forum post that is the same problem, but cannot believe we're doing something so different from the norm that would mean no one else has experienced it.
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