zabbix agent to zabbix server communication through stunnel doesn't work

[espai]

Hello forum,

I'm succesfully monitoring a number of Windows and Linux servers with zabbix using psk-encrypted tunnels.

There are however two Synology NASes I want to monitor, for which only a TLS-unaware zabbix agent is available
(installed through entware-ng repository using opkg).

Unsecured communication between passive zabbix agents and the zabbix server is working nicely.

In order to secure the communication between the zabbix agents on the two NASes in question and my zabbix server
I've set up two tunnels with stunnel.

The two stunnel tunnels do work - I've managed to write something on a terminal session on the NASes using netcat.

The communication between the zabbix agent on the NASes and the zabbix server however fails.

Here's my setup

zabbix agent:

Server = localhost
ListenPort = <HIGHPORT_BELOW_32767>

zabbix server:

Configuration -> Hosts -> Interface: 127.0.0.1: <HIGHPORT_BELOW_32767>

However the zabbix server cannot connect to the zabbix agents over the stunnel.
Under Configuration -> Hosts -> Availability the ZBX icon is red with the following remark:

Get value from agent failed. Cannot connect to [[127.0..01]:<HIGHPORT_BELOW_32767>]: [111] Connection refused

Any ideas anyone?

[kloczek]

first try t confirm that communication over tunnel is working

[espai]

Hello kloczek,

It's working now - I've solved the riddle myself.

I've simply swapped roles and configured the NASes as stunnel servers and the zabbix server as a stunnel client.
Now I'm receiving data from the zabbix agents on the NASes over stunnel.

Case dismissed.