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How to use a local IIS page as a web proxy for Firefox?

Not an NSA agent (at all!)
Not an NSA agent (at all!)
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I created a page to serve as a web proxy and have it on my local IIS. When I run it in Visual Studio and set a breakpoint - it's hit, so the page is definitely there.

I then set that page as the address in Firefox->Options->Advanced->Network->Settings->Manual Proxy configuration->http proxy (and port 80), and then I try to browse some web page (on the web. Not https) and get an error "server not found". This might indicate that my page is set up wrong. But that's not my question.

My question is: the breakpoint on that page in Visual studio is not being hit, though the project is being debugged. This seems to mean that Firefox is not even trying to connect to it. Why?

I created a page to serve as a web proxy and have it on my local IIS. When I run it in Visual Studio and set a breakpoint - it's hit, so the page is definitely there. I then set that page as the address in Firefox->Options->Advanced->Network->Settings->Manual Proxy configuration->http proxy (and port 80), and then I try to browse some web page (on the web. Not https) and get an error "server not found". This might indicate that my page is set up wrong. But that's not my question. My question is: the breakpoint on that page in Visual studio is not being hit, though the project is being debugged. This seems to mean that Firefox is not even trying to connect to it. Why?

Okulungisiwe ngu Not an NSA agent (at all!)

All Replies (3)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
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ispiro said

I created a page to serve as a web proxy and have it on my local IIS. When I run it in Visual Studio and set a breakpoint - it's hit, so the page is definitely there.

Sorry, I'm not sure what this means, so just to confirm: If you enter the page's address in Firefox's address bar (with "No proxy" set), can Firefox load the page?

That would confirm that Firefox can reach the proxy.

In our general help article on "Server Not Found" errors, the next thing to check would be "If you use a proxy server, make sure that the proxy server can connect to the Internet."

I wonder whether this might be a DNS issue. With the proxy set, if you try to access a site by IP address, can Firefox access it through the proxy?

Not an NSA agent (at all!)
Not an NSA agent (at all!) Umnikazi wombuzo
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jscher2000 said

If you enter the page's address in Firefox's address bar (with "No proxy" set), can Firefox load the page?

Yes.

make sure that the proxy server can connect to the Internet.

As far as I understand - irrelevant here. The breakpoint is never hit. So Firefox never tries contacting my web-proxy-page.

With the proxy set, if you try to access a site by IP address, can Firefox access it through the proxy?

What happens is that the address bar changes to show the site's domain name (perhaps it's cached?) and I then get the same exception. But, again, I think it's irrelevant. The point is that Firefox doesn't even try to contact my web-proxy-page.


(The proxy-page is an ashx page - a generic handler using ASP.net. And I'm using IIS, not IIS-express.)

Okulungisiwe ngu Not an NSA agent (at all!)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
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One other thought: The instructions I've seen for configuring Firefox's connection settings refer to entering a host name in Firefox's proxy settings (e.g., on MDN).

If you are entering more than your localhost host name or IP address (whatever you are using), try entering only the host name or IP address in case Firefox is not extracting it from the URL in the expected manner.