Zabbix's discovery facilities consist of a set of rules that periodically scan the network, looking for new hosts, or disappearing ones, according to predetermined conditions.
The three methods Zabbix can use to check for new or disappeared hosts, given an IP range, are:
The availability of a Zabbix agent
The availability of an SNMP agent
The response to simple external checks (FTP, SSH, and so on)
These checks can also be combined, as illustrated in the following example:
As you can see, when enabled, this rule will check every hour, in the IP range 192.168.1.1-254, for any server that:
Returns an SNMPv3 value for the
SNMPv2-MIB::sysDescr.0OIDIs listening to and accepting connections via SSH
Has an HTTPS server listening on port
8000
Be aware that a discovery event will be generated if any one of these conditions is met. So, if a discovery rule has three checks defined and a host in the network responds to all three checks, three events will be generated, one per service...