Request filtering in IIS (Internet Information Services) is a security feature that allows you to control and filter incoming HTTP requests to your web server. It enables you to specify rules and conditions to allow or deny requests based on various criteria such as file extensions, HTTP verbs (GET, POST, etc.), query strings, headers, and more. This capability is essential for enhancing the security and performance of your web applications by blocking malicious requests and restricting access to certain resources.
Here's how to configure request filtering in IIS:
Open IIS Manager:
- Press
Win + R, typeinetmgr, and press Enter to open the Internet Information Services (IIS) Manager.
- Press
Select Your Website:
- In the Connections pane on the left, expand your server node and click on the "Sites" node to see a list of websites hosted on your server. Select the website for which you want to configure request filtering.
Open Request Filtering:
- In the right-hand Actions pane, click on "Request Filtering." This will open the Request Filtering configuration for the selected website.
Add Filtering Rules:
- To add a request filtering rule, right-click on the specific category where you want to create a rule (e.g., "File Name Extensions," "HTTP Verbs," "Headers," etc.) and select the corresponding "Add" option. For example, to deny requests for a specific file extension, right-click on "File Name Extensions" and choose "Deny File Name Extension."
Configure Filtering Rules:
- After adding a rule, you'll need to configure its properties. For example, if you're denying requests with a specific file extension, enter the file extension (e.g., ".php") and configure any other options such as "Allow unlisted file name extensions" if needed.
Apply Changes:
- After configuring your request filtering rules, click on "Apply" in the right-hand Actions pane to save your changes.
Test Request Filtering:
- To ensure that your request filtering rules are working correctly, test your website by making requests that should match the configured criteria. You should observe the expected behavior, whether it's allowing or denying access based on your rules.
Request filtering helps protect your web applications from common attack vectors like SQL injection, cross-site scripting (XSS), and more by blocking malicious requests. It also allows you to optimize server performance by denying access to unnecessary or potentially harmful resources. Properly configuring request filtering is an essential part of securing your IIS-hosted web applications.