I have serveral ASP.NET web sites running on a web server with IIS. All sites work fine when accessed with browser. Recently I wrote a simple .NET application that tests the availability of the sites, via making simple HttpRequests. This application return 404 error for some of the sites, even though sites can be accessed via browser. Furthermore, there are many other web sites that are using same application pool and that work just fine in both browser and testing application.
This make me think the problem is in the IIS settings of the web sites that are not workng, but I'm not able to find it right now.
I cheched the IIS logs, and haven't found anything useful. Logs for failed requests return:
2009-10-06 14:37:41 W3SVC1700126462 XXX.XXX.XXX.XXX GET /Default.aspx - 80 - XXX.XXX.XXX.XXX- 404 0 0
Requests for sites that are ok return something like: 2009-10-06 14:40:11 W3SVC1643909652 XXX.XXX.XXX.XXX GET /Default.aspx - 80 - XXX.XXX.XXX.XXX - 200 0 0
I also checked HTTPERR logs, but the only thing I found were Timer_ConnectionIdle errors.
So, can someone suggest me some other way to approache the problem and find out why my application gets 404 on some sites, while they still work fine in browser.