All of our servers are monitored by two separate probing systems 24
hours per day.
Our primary monitoring system lies internal to our own network and
probes each of your virtual servers once every five minutes. A HEAD
request is made from each virtual server and the monitoring program
looks to ensure that the web server is accepting connections, that it
is processing requests, and that when it processes a request it does
not return an error.
Our secondary monitoring system lies external to our network and
probes each server once every five minutes to make sure that all
services are still running (HTTP, FTP, POP3, IMAP, SMTP, telnet,
etc.).
If either monitoring system logs an error condition, an alert email
is sent to our support staff and our support staff is also paged.
Because our primary monitoring system actually makes a HEAD request
from each virtual server, you will notice an unusually high number of
hits for your main index page ("/") in your nightly statistics. The
probing itself accounts for approximately 1.5 Megabytes of transfer
per month (negligible).