Has Anyone Had Issues With ASP.NET 4.0 URL Routing?

[TroyCarlson]

I'm seeing some odd results in my SEOMOZ results with a new site I just released that is using the ASP.NET 4.0 URL routing.  I am seeing thousands(!) of duplicate results, for instance, because the crawl has uncovered something like this:

http://www.mysite.com/
http://www.mysite.com/default.aspx (so far, so good, though I wish it wouldn't show both)
http://www.mysite.com/default.aspx/about/ (what the heck -?)
http://www.mysite.com/default.aspx/about/about/ (WTF!?)
http://www.mysite.com/default.aspx/about/about/products/ (and on and on ad infinitum)

I'm also seeing problems pop up in my sitemap because extensionless urls have an odd "eurl.axd/abunchofnumbersgohere" appended to the end of every address which is breaking links.

sigh

Buyer beware.

I've found articles that discuss the "eurl.axd" issue here and there (this one seems very good), but nothing about the weird crawl issue I outlined above.  Any advice?

[benjaminspak]

I'm not to familiar with IIS myself, however I found a few good articles here on SEO Moz. You can also contact the author's of each post, I'm sure they know what to look for to fix it.

http://www.seomoz.org/blog/what-every-seo-should-know-about-iis

Additional Reading:

http://www.seomoz.org/ugc/iis-case-folding-robots-and-results

http://www.seomoz.org/ugc/iis-seo-issues