This may be the most mysterious problem I have ever encountered.
We have an IIS7 installation with 3 websites, each of which has its own application pool. Once a day, for about an hour, one of them falls.
What I mean by "down down" is:
- It stops responding to dynamic page requests (e.g. default.aspx), but will serve static files in order (logo.png).
- Wireshark tells me that these dynamic page requests actually return HTTP 500 Internal Server errors, but I don't see the error in the browser. I just see the browser spinning.
- If I enter locally in the field and search around , everything works fine . All pages are pulled, so a database is requested. All this seems perfectly normal.
- There are no errors in the event log.
- There are no errors recorded in our internal (Application-level) error log.
- The main IIS log file, which I thought was logging every request, shows these requests without recording .
And, if I restart the application pool for the website, everything will return immediately. Or, if I just wait an hour or so, he will be back.
So I excluded:
- Problems with DNS, since I have no problems servicing the terminals in the field by host name.
- Database problems as the site works fine when I am local in the field and browsing
- HTTP, wirehark, .
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