See the Explanation below for step by step instructions.
Explanation
Here are the steps and explanations for creating a policy that can be linked to the planned application gateway and block connections from IP addresses in the 131.107.150.0/24 range:
* To create a policy, you need to go to the Azure portal and select Create a resource. Search for WAF, select Web Application Firewall, then select Create1.
* On the Create a WAF policy page, Basics tab, enter or select the following information and accept the defaults for the remaining settings:
* Policy for: Regional WAF (Application Gateway)
* Subscription: Select your subscription name
* Resource group: Select your resource group
* Policy name: Type a unique name for your WAF policy
* On the Custom rules tab, select Add a rule to create a custom rule that blocks connections from IP addresses in the 131.107.150.0/24 range2. Enter or select the following information for the custom rule:
* Rule name: Type a unique name for your custom rule
* Priority: Type a number that indicates the order of evaluation for this rule
* Rule type: Select Match rule
* Match variable: Select RemoteAddr
* Operator: Select IPMatch
* Match values: Type 131.107.150.0/24
* Action: Select Block
* On the Review + create tab, review your settings and select Create to create your WAF policy1.
* To link your policy to the planned application gateway, you need to go to the Application Gateway service in the Azure portal and select your application gateway3.
* On the Web application firewall tab, select your WAF policy from the drop-down list and select Save