Detect if Zabbix agent is down

[coolblue99]

I have a Linux server behind a firewall with only active checks set up. Now if the server or the agent itself fails, I don't get an error message about it. How can I get the Zabbix server to notice that an agent is no longer delivering data?

[markfree]

I think "Zabbix agent active" native template has an "Zabbix agent ping" item with a "Zabbix agent is not available" trigger.
This trigger uses a "{$AGENT.NODATA_TIMEOUT}" macro with 30m value.

Doesn't that template works for you?

[markfree]

Trigger "Zabbix agent is not available" in "Zabbix agent active" template uses "nodata()" function.
It seems to me that it would sufice.

[Spectator]

I think my question is similar.
There is an active proxy with "Template OS Linux by Zabbix agent active" and "Template App Zabbix Proxy" templates.
If the Zabbix server loses connection to this proxy, I will not receive any alert.
This is normal? What can I do?
There is one such trigger in the "Template OS Linux by Zabbix agent active" template - which I think should alert you: "Zabbix agent is not available (or nodata for {$ AGENT.NODATA_TIMEOUT})"

On the zabbix server, I use the following iptables command to disconnect from the proxy for the sake of the test:
iptables -I INPUT -s xxx.xxx.xxx.xxx -j DROP
(xxx.xxx.xxx.xxx is the IP address of the proxy)

[markfree]

I think my question is similar.
There is an active proxy with "Template OS Linux by Zabbix agent active" and "Template App Zabbix Proxy" templates.
If the Zabbix server loses connection to this proxy, I will not receive any alert.
This is normal? What can I do?
There is one such trigger in the "Template OS Linux by Zabbix agent active" template - which I think should alert you: "Zabbix agent is not available (or nodata for {$ AGENT.NODATA_TIMEOUT})"

On the zabbix server, I use the following iptables command to disconnect from the proxy for the sake of the test:
iptables -I INPUT -s xxx.xxx.xxx.xxx -j DROP
(xxx.xxx.xxx.xxx is the IP address of the proxy)

What's your Zabbix Server version?
Check if your "Template OS Linux by Zabbix agent active" is linked to "Zabbix agent" template.
I'm not sure, but I think it should be linked to "Zabbix agent active" template.

[Spectator]

What's your Zabbix Server version?
Check if your "Template OS Linux by Zabbix agent active" is linked to "Zabbix agent" template.
I'm not sure, but I think it should be linked to "Zabbix agent active" template.

The Zabbix version is 5.0.17 LTS

This templates are linked to the proxy:
Template App Zabbix Proxy, Template OS Linux by Zabbix agent active (Template Module Linux block devices by Zabbix agent active, Template Module Linux CPU by Zabbix agent active, Template Module Linux filesystems by Zabbix agent active, Template Module Linux generic by Zabbix agent active, Template Module Linux memory by Zabbix agent active, Template Module Linux network interfaces by Zabbix agent active, Template Module Zabbix agent active)

Did you mean the underlined templates?
If so, do you or anyone else have any further ideas?

[cyber]

Agent.ping may not give results here as there are only active items. agent.ping is OK if you have it as passive item.
But still, you can use any other item for nodata() trigger. If you have there items, that are regularly updated...

[cyber]

ok ..You are right...I did not look into the template. It really uses agent.ping as active item... It seemed kind of weird for me to use agent to ping itself instead of proxy/server.. I have always used it as passive item (so you get nice green ZBX icon also).
But we do not know what items/trigger topic starter has installed. Maybe it is something completely custom and no agent template is there.. So the suggestion stays, use whatever regularly updated items with nodata() function for trigger..