SystemwebServerurlRewrite

System.webServer/urlRewrite is a configuration section in Internet Information Services (IIS) that defines URL rewriting and redirection behavior for a website. It is implemented by the URL Rewrite Module and configured in the site's web.config file under the system.webServer element. When installed, the module intercepts requests and can rewrite the requested path, redirect a client to a different URL, or modify response content through outbound rules.

Structure and usage: The rewrite configuration contains a rewrite element, which holds one or more rules and optional outboundRules. Each rule has a name, an enabled flag, and a stopProcessing attribute. A rule includes a match element (usually matching the URL path with a regular expression), optional conditions (based on server variables, HTTP headers, or query strings), and an action element that specifies the operation. The action's type can be Rewrite, Redirect, CustomResponse, or AbortRequest, and it provides the target URL. For Redirect actions, a redirectType (Permanent or Temporary) can be set, and appendQueryString controls whether the query string is preserved. Outbound rules operate on the response content to rewrite links or references.

Common uses: Typical scenarios include enforcing HTTPS, canonical host redirection, removing or adding trailing slashes, and rewriting clean, SEO-friendly URLs to internal resources or scripts. Outbound rules are used to adjust links in HTML or other content as it leaves the server.

Notes: The feature requires the URL Rewrite Module to be installed on the IIS server. Rules are evaluated in order, and poorly designed rules can cause performance issues or redirect loops, so careful planning and testing are advised.