Diagnosing weirdness
--------------------

If you get a lot of messages like "no router found for <host>", then
<host> probably hasn't been addressed by the router(s) you have 
configured for that network.  Imagine a situation like this:

 +----------+   +--------+  +----------+     +------------+
 | Router 1 |   | Target |  | Router 2 +-----+ (Internet) |
 +----------+   +--------+  +----------+     +------------+
      |              |            |
------+--------------+------------+----

In this case, imagine a host that only talks to the Internet (via router 
2) and never the internal network (behind router 1).  If you only have 
router 1 in your sdig.conf, you will never be able to track this target.

The solution is to add router 2 as another entry, since it will have an 
ARP entry for the host.

Obviously, this only happens when the sdig host is also not behind router 
1, as sdig will send out some pings to kickstart ARP when nothing happens 
at first.

This can also happen if you try to dig switch IP addresses.  Switches 
generally don't have a lot to say, especially to each other.  If you need 
to make this work, you may have to log into each switch and have them ping 
the target switch so they know where it is first.
