title: systemd-activate socket activation for UDP daemons
body: <p>I like using <code>systemd-activate(8)</code> for <strong>testing</strong> socket-activated daemons during development,
  however, it seems it only listens for TCP connections:</p>
  
  <pre><code>% /usr/lib/systemd/systemd-activate -l 5700 ./prog
  Listening on [::]:5700 as 3.
  
  % netstat -nl |grep 5700
  tcp6       0      0 :::5700             :::*             LISTEN 
  </code></pre>
  
  <p>I am using a program that handles datagrams (UDP).  How can I make <code>systemd-activate</code> listen on a UDP port?  Or is there a 
  simple way to do this using other tools, without going to the trouble of crafting and installing a systemd unit file?</p>