<p><strong>Cancelling Inheritance of String Values</strong></p>
<p>In some cases you may not want your host, service, or contact definitions to inherit values of string variables from the templates they reference. If this is the case, you can specify "<strong>null</strong>" as the value of the variable that you do not want to inherit.</p>
<p><strong><br>Additive Inheritance of String Values</strong></p>
<p>Nagios gives preference to local variables instead of values inherited from templates. In most cases local variable values override those that are defined in templates. In some cases it makes sense to allow Nagios to use the values of inherited <em>and</em> local variables together.</p>
<p>This "additive inheritance" can be accomplished by prepending the local variable value with a plus sign (<strong>+</strong>).  This features is only available for standard (non-custom) variables that contain string values.</p>