anchor.diff:   and forward ports.
    UPnP support is beta, and may not work for any number of reasons:
    <ul>
  - <li>No UPnP-compatible device present
  - <li>UPnP disabled on the device
  - <li>Software firewall interference with UPnP
  - <li>Bugs in the device's UPnP implementation
  - <li>Multiple firewall/routers in the internet connection path
  - <li>UPnP device change, reset, or address change
  +<li class="tidylist">No UPnP-compatible device present
  +<li class="tidylist">UPnP disabled on the device
  +<li class="tidylist">Software firewall interference with UPnP
  +<li class="tidylist">Bugs in the device's UPnP implementation
  +<li class="tidylist">Multiple firewall/routers in the internet connection path
  +<li class="tidylist">UPnP device change, reset, or address change
    </ul><br>
    Reviewing the <a href="peers.jsp#upnp">UPnP status</a> may help.
    UPnP may be enabled or disabled above, but a change requires a router restart to take effect.
  
positive.code:     with "SSU introductions" to relay traffic. Most of the options above are for special situations,
      for example where UPnP does not work correctly, or a firewall not under your control is doing
      harm. Certain firewalls such as symmetric NATs may not work well with I2P.
   </p>
  <!-- let's keep this simple...
  <input type="submit" name="recheckReachability" value="Check network reachability..." />
  -->
  
negative.code:  that you may have multiple firewalls, for example both software packages and external hardware routers.
   If there is an error, the <a href="logs.jsp">logs</a> may also help diagnose the problem.
   <ul>
  <li class="tidylist"><b>OK</b> - Your UDP port does not appear to be firewalled.
  <li class="tidylist"><b>Firewalled</b> - Your UDP port appears to be firewalled.
       As the firewall detection methods are not 100% reliable, this may occasionally be displayed in error.
       However, if it appears consistently, you should check whether both your external and internal
       firewalls are open on port 8887. I2P will work fine when firewalled, there is no reason for concern.
  