Use case

Problem:

A remote location where Zabbix proxy is located does not allow incoming connections. At the same moment location where Zabbix server is located does not allow incoming connections as well. So, neither Zabbix proxy in active or passive mode is not usable for such scenarios.

Possible solution:

Additional Zabbix proxy can be installed on "neutral" territory (next to Zabbix proxy, Zabbix server, or really in the middle) and then this additional Zabbix proxy would accept data coming from remote Zabbix proxy and then will provide this data to Zabbix server.