Hi, I know how to canonicalise the case of URLs on incoming request to IIS7.5, in fact, there's a built in rule template to start from. But how about outbound (without changing the code)? This is where I got to so far: <outboundRules> <rule name="Outbound lowercase" preCondition="IsHTML" enabled="true"> <match filterByTags="A" pattern="[A-Z]" ignoreCase="false" /> <action type="Rewrite" value="{ToLower:{R:0}}" /> </rule> <preConditions> <preCondition name="IsHTML"> <add input="{RESPONSE_CONTENT_TYPE}" pattern="^text/html" /> </preCondition> </preConditions> </outboundRules> However, IIS barfs on the action with a 500 implying an invalid web.config, probably on the {ToLower:XXXX} which I stole from the MS-supplied inbound rule template. Anyone know how to do this? Anyone know where the options are fully documented (my GoogleNinja skills failed me: I found this but "Specifies value syntax for the rule. This element is available only for the Rewrite action type" is not really comprehensive). Thanks, Damian