I have no idea why this isn't working. I've tried creating map rules and then rewriting and redirecting the URL. I've tried just redirecting it with a simple rewrite rule and no matter what, the only time I can get it to work is if I set the match URL to match this regex .*.

I'm trying to redirect webmail.example.com to mail.example.com. Seemed like it would have taken but a couple seconds; boy was I wrong. I'm thinking I must be doing something wrong with the regex, but I'm not sure what as when I test it it seems to work fine.

            <rule name="webmail" patternSyntax="ECMAScript" stopProcessing="true">
                <match url=".*webmail.*" />
                <conditions logicalGrouping="MatchAll" trackAllCaptures="false">
                </conditions>
                <action type="Redirect" url="https://mail.example.com:8000" appendQueryString="false" logRewrittenUrl="true" />
            </rule>