adds small explanation to the routed subnet

src/pages/how-to/manage-posture-checks.mdx

@@ -193,5 +193,6 @@ When we are connected somewhere outside the office, we can observe:
 <p>
     <img src="/docs-static/img/how-to-guides/netstat-routes-grep-external.png" alt="high-level-dia" className="imagewrapper"/>
 </p>
+Notice that the subnet `192.168.1.0/24` is routed through our Wireguard interface (`untu100`).
 
 This concludes this Posture Check example.