I am using IIS 7 on Windows 2008 Server for an ASP.NET 4 application using Bootstrap. The server has a private IP address to use at work, but is also accessible through a public IP address from outside. Our Internet access provider does the forwarding for us. The server is also running the F-Secure antivirus system.
When I browse the web site from the server itself, using either the private IP or the public one, it works fine. But when I use a remote client (using the public IP, obviously), it works randomly. A typical scenario goes like this:
- I type the web site URL on my browser. I get home page.
- I click on a link to navigate to another page. I get an INET_E_RESOURCE_NOT_FOUND error.
- I hit refresh on the browser. I get the page.
- I click on another link. I get the page.
- I click on another link. I get an INET_E_RESOURCE_NOT_FOUND error.
And so on and so forth. It is apparently random. Sometimes the server returns the page, sometimes I get the INET_E_RESOURCE_NOT_FOUND error. It happens from every client I have tried, from Edge on a Windows 10 machine to Safari on an iPhone.
Some other times, the server fails to deliver the home page when I first browse to it from a client computer. I retry a few times to no avail. And then, after perhaps 5 or 10 refreshes, I get the page. And from that point on, it works OK until, eventually, it fails again.
As far as I understand, INET_E_RESOURCE_NOT_FOUND does not mean that a page was not found (that would be a 404), but that the server could not be found. It is usually associated with a DNS or proxy error.
I have been looking at IIS log files. As far as I can see, sometimes logging gets interrupted with entries such as this one:
GET /fonts/glyphicons-halflings-regular.woff - 80 - 188.8.131.52 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/52.0.2743.116+Safari/537.36+Edge/15.15063 404 3 50 78
Apparently, the client is trying to get a fonts file and the server returns a 404 error. The font file is on the server in the right folder, so I am not sure why it's failing to find it.
EDIT. I have now fixed the issue with the font file (which was due to a missing MIME type entry on IIS), but the random INET_E_RESOURCE_NOT_FOUND errors remain. The 404 with the font file is likely to be a red herring.
EDIT. I have another issue with this same web site, which may be related. Please see here: https://stackoverflow.com/questions/43814006/smtpexception-in-asp-net-application-with-remote-browser
Any ideas? Thanks.