Difficulty with simple ASP rewrite rule

I have the page:

~/forum/forum_faq.html

In my logs I've seen 404 requests to:

~/forum_faq.html

For some reason, so I attempt to fix it with this rule:

<rewrite url="~/forum_faq.html$" to="~/Handlers/PermRedi开发者_C百科rect.ashx?URL=forum/forum_faq.html" processing="stop" />

The perm redirect file just does a 301 redirect to the given location. When this rule isn't there, I can access forum/forum_faq.html just fine. When I add the rule, I get a:

This web page has a redirect loop The web page at http://127.0.0.1/forum/forum_faq.html has resulted in too many redirects. Clearing your cookies for this site or allowing third-party cookies may fix the problem. If not, it is possibly a server configuration issue and not a problem with your computer.

Any ideas what's going on?

Is suspect what is happening is Forum is an ASP.NET application in IIS. Your ~/forum_faq.html$ is therefore matching the path /forums/forum_faq.html sending it via your handler which then redirects to /forum/forum_faq.html in an infinite loop.