You probably want to look at something like URL Rewrite to rewrite URLs to more user friendly ones rather than using a simple httpRedirect
. You could then make a rule like this:
<system.webServer>
<rewrite>
<rules>
<rule name="Rewrite to Category">
<match url="^Category/([_0-9a-z-]+)/([_0-9a-z-]+)" />
<action type="Rewrite" url="category.aspx?cid={R:2}" />
</rule>
</rules>
</rewrite>
</system.webServer>