Add GPLv2 + linking exception to the source

[pingcheck] / Readme

     Table of Contents
=======================================
1. Introduction
2. Configuration File
3. Command line
4. References



1.   Introduction
=======================================
This application provides means to check the availability of remote hosts
through pings to them.


1.1. Rationale
---------------------------------------
The application uses ICMP echo requests messages to verify if a given host
is available or not.

The host's address can be an IP or a DNS.


1.2. How to use
---------------------------------------
There are many ways to invoke the application, the simplest is just type:
  ./pingcheck
which uses the configuration values from the configuration file (describled in
the Configuration File section).


1.3. Resources
---------------------------------------
Further information about the problem domain can be found in the References
section.


1.4. Legal Issues
---------------------------------------
All rights reserved to Intra2net AG.



2.   Configuration file
=======================================
In this section are describled the configuration items, along with they
possible values and meanings. This section is organized in each major
configuration block.


2.1. General
---------------------------------------
This configurations are shared among and affect all the hosts.
- source-network-interface: the local network interface from where the ping
  packages with originate.
- nameserver: the server which the hosts names will be resolved. It is the
  lookup server which the application will query first. If left blank or omited,
  it will use the /etc/resolv.conf.
- hosts-down-limit: an absolute number, which ranges from 0 to the number of
  hosts available. This value represents the minimum number of hosts that have
  to fail (i.e. do not reply to the ping) in order to alert any external system.
- ping-fail-limit: percentage of pings to a host that can fail. If the
  percentage of failed pings to a host exceed this number, then the host is
  considered down.
- status-notifier-cmd: the command line that is called when a host is down, or
  up. Accepted variables are:
    ${status} - down or up
- link-up-interval: how long (in minutes) the pings must be returned with
  success in order to consider the link up, or stable.
- link-down-interval: how long (in minutes) the pings must fail, in order to the
  application consider the link down.


2.2. Host
---------------------------------------
- name: the DNS or IP of the host to ping. Take in consideration that, if a
  DNS is given, the application pings all IPs in the look up table, however, if
  IP is provide, it is the only which will be pinged.
- interval: the host will be pinged every "interval" seconds.



3.   Command line
=======================================
The command line accepts the general configuration file options plus the
following:
- config-file: command line to specify a file where the hosts and other
  configuration information are provided.



4.   References
=======================================
[1]  http://tools.ietf.org/html/rfc792
[2]  http://en.wikipedia.org/wiki/Ping
[3]  http://en.wikipedia.org/wiki/Internet_Control_Message_Protocol
[4]  http://www.boost.org/doc/libs/1_45_0/doc/html/boost_asio.html
[5]  http://www.boost.org/doc/libs/1_45_0/doc/html/program_options.html