Add a note about ICMP rate-limiting

templates/home.html

@@ -28,7 +28,8 @@ guide</a>.</p>
 <p>
 <form action="/submit" method="POST">
 <label for="target">Target:</label>
-<input type="text" name="target" id="target" value="{{ request.remote_addr|ipaddress_pp|not_dn42 }}"/><br />
+<input type="text" name="target" id="target" value="{{ request.remote_addr|ipaddress_pp|not_dn42 }}"/>
+<span style="margin-left: 1em;"><strong>Note:</strong> the target may block or rate-limit ICMP (e.g. Fritz!Box routers)</span><br />
 <input type="checkbox" id="public" name="public" />
 <label for="public">Public?</label><br />
 <input type="submit" value="Launch" />