Standard tools in non-standard situations
Monitoring tools like IPHost Network Monitor provide a set of built-in monitor types to handle most routine tasks.
They are sufficient to handle the majority of monitoring needs; it is often necessary to make sure a given type of service is accessible without actual checking.
However, a number of tasks may require something, not present in the distribution. What is the beat approach in such a case
A real-life example: you would like to monitor users' inbox sizes and warn them, if those inboxes grow too large.
One of approaches could be to make a script that ssh's to the mail server, runs 'ls' program at a given mailbox and returns its size in whatever units required.
However, if mail inbox directory can be accessed as a network share, the task could be solved using built-in file size monitor type. Moreover, if the monitor is named after the mailbox user's part, the alert can be built in such a manner so that it could notify the mailbox' owner of the quota limit trespassed.
The wheel reinvented
There can be several solutions to a problem. For example, to check a given user's presence at a site we could analyse that user's profile page and look for a text pattern.
However, it would mean we stress not only the database the data are taken from, but a Web server as well. When monitoring a site it is often a good idea not to overwhelm the site with monitoring itself. Too fast loading Web pages may create an unnecessary stress on the site.
The above task could be solved by a slightly different means: monitoring a SQL database. If a proper SQL query is constructed, its first column returned is interpreted as a performance value. Thus, most of SQL-driven sites activity may be monitored just by creating the correct SQL query, able to return a numeric result.
To sum up: when monitoring task may be solved by checking files size, result of a SQL query, string found in HTTP(S) response - it's better to solve the task in that manner.
Custom scripts can be used when a task, not easily reduced to the cases above, must be solved. E.g., when a file of a given size, modification time and access permissions must be present in a known location.
And, finally, a good suggestion: if you are using a monitoring tool and failed to solve a task by available means, it's always worth contacting the developer(s) and suggesting a new monitor type.
How often could you encounter a network monitoring task when built-in means of the monitoring tool you are using aren't enough?
