This is shaip. a Stateful Hierarchy Aware Icmp Prober
-----------------------

shaip was developed to solve the problems with using ICMP ping to
monitor a distributed network from a central point. Its primary
aim is to generate notification messages when network devices 
or servers become unavailable, and specifically to avoid generating
spurious alarms for equipment located behind a router or switch
when the router/switch itself goes down.

--------------- Config file ----------------
Input data to the program is a file with two or three colon-separated
fields on each line:

foo:192.168.0.1
bar:192.168.1.10:foo

The first field is a label that will be presented in messages and used
as a key in the state file that shaip uses to keep track of the last
state of the device.

The second field is the hostname or an IP address.

The third field is the _parent_ of the node. If this field is empty,
the device is considered to be a root of its own tree.

The lines do not need to be in any particular order.

---------------- State file ----------------
The state file is maintained by shaip and consists of lines with two
or three fields, colon-separated:

bar:down:Tue Sep  7 09.01.11 2004
foo:up

The first field is the label or device name, same as the first field
in the config file.

The second field is the state, which can be "up", "down", "warning" or
"error".

The third field, if present, is the date and time the device went
"down", and will only be there if the device is actually down.

---------------- Command line ----------------

shaip -c <config file> -s <state file> [-a] [-n <number of packets>]
      [-P <pause between packets>] [-T <timeout for replies] [-v] [-t]
      [-w]

The optional parameters are as follows:

 -a		Report state for all devices, regardless of last state.
 -n #		Send # icmp probes to each device. Default is 3.
 -P #		Pause # ms between packets. Default is 5.
 -T #		Collect replies for # seconds after sending all the
		probes. Default is 2.
 -v		Verbose execution. Adding more "-v"'s increases
		verbosity.
 -t		Report mean roundtrip time for replies.
 -w		Report WARNING state as WARNING instead of UP

---------------- More info --------------------

The state is determined as follows:

If there is an error in transmitting an ICMP probe, the device's state
will be ERROR.

If no replies are received, the state will be DOWN.

If replies are received to all the probes, the state will be UP.

If some replies are received but some are missing, the state will be
WARNING. This will be treated as UP unless "-w" is given.

Unless "-a" is given, shaip will prune all subtrees below any node
that is DOWN before reporting the state of the rest of the nodes. The
nodes that are ignored in this way are effectively treated as "UP", by
the program. Thus, when a downed device comes up again, nothing else
will be reported unless one of the devices behind it turns out to be
down too.