How to handle bad requests in asp.net

I 开发者_开发问答am using asp.net 3.5, there are some requests with special characters (for example ./ and <) return "bad request" by asp.net application, it looks like the Application_Error method in Global.asax.cs cannot handle these errors, are there any other methods to handle these request errors?

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Requests examples:

http://localhost/abc./abc.aspx

http://localhost/ab<c.aspx

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This is being caused because the characters specified can cause security issues. Further information.

Take a look at A potentially dangerous Request.Form value was detected from the client for how to handle these