Created on 2005-07-11 by Rainer Gerhards.
AliveMon can monitor any device supporting TCP/IP. At the minimalist
level, AliveMon use "ping" (aka ICMP Echo) to check if a device is responding or
not. Ping does not ensure the device is fully operational, but it tells you that
it is powered up, connected to the network and the TCP protocol stack is working.
Please note that ping might be disabled by firewalling, in which case AliveMon
can not use this method of monitoring.
In addition to simple ping, AliveMon provides application-level monitors.
It offers generic monitors for any TCP based services as well as some
specialized monitors for mail, web (http) and game servers. These monitors allow you
to monitor at the application level. For example, with the web monitor you can
check that your web server is actually responding to http request. If the web
server hangs, a ping based monitor would be unable to detect the malfunction. At
the application-level, however, this can be easily detected.
Application-level monitors also allow you to monitor a system when ping is
disabled by firewalling.