===== Nagios Free or Custom Variables =====
Supervision -> Hosts -> $HOSTS$ -> Addon settings, Free variable definitions:
<code>
_SECONDADDRESS
172.19.64.88
</code>

To use with services: $_HOSTSECONDADDRESS$

==== References ====
  * https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/4/en/customobjectvars.html