Add the ssrf module

ssrf/pom.xml

@@ -0,0 +1,60 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0">
+  <modelVersion>4.0.0</modelVersion>
+
+  <!-- Inheriting spring-boot-starter-parent so every version below is Boot-managed. The
+       feature this module demonstrates - org.springframework.boot.http.client.InetAddressFilter
+       - is new in Boot 4.1 and lives in spring-boot-http-client, which arrives transitively
+       with spring-boot-starter-web. See docs/01-what-ssrf-costs-you.md. -->
+  <parent>
+    <groupId>org.springframework.boot</groupId>
+    <artifactId>spring-boot-starter-parent</artifactId>
+    <version>4.1.1</version>
+    <relativePath/>
+  </parent>
+
+  <groupId>com.ankurm</groupId>
+  <artifactId>ssrf-inet-address-filter</artifactId>
+  <version>1.0</version>
+  <packaging>jar</packaging>
+
+  <properties>
+    <java.version>25</java.version>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-web</artifactId>
+    </dependency>
+    <!-- Boot 4 modularised the HTTP client story: spring-boot-starter-web does NOT bring an
+         auto-configured RestClient.Builder, and it does not put InetAddressFilter on the
+         classpath either. This starter is what pulls in spring-boot-restclient and, through
+         it, spring-boot-http-client. See docs/05-wiring-it-up.md. -->
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-restclient</artifactId>
+    </dependency>
+    <!-- Present ONLY so the apacheclient profile has a second request factory to select.
+         Which client is on the classpath changes WHERE the filter runs - a DNS resolver for
+         Apache, a ProxySelector for the JDK client. See docs/04-where-the-filter-runs.md. -->
+    <dependency>
+      <groupId>org.apache.httpcomponents.client5</groupId>
+      <artifactId>httpclient5</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-test</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-maven-plugin</artifactId>
+      </plugin>
+    </plugins>
+  </build>
+</project>