want to be alert when zabbix agent down or can not be connected

[wangjf]

i use zabbix 2.0.3.

when a monitored host was incorrectly configured with firewall by some one ,like forbidden all incoming and outcomming tcp connection, zabbix server can not connect to the agent ,and the host 's 'Z' word will be red and indicate an error:
Get value from agent failed: *** Cannot connect to [<IP>]:10050 [No route to host].

the problem is how can i be alerted when this happens ? i have been tried items like host.status or zabbix[host,agent,available] ,the former item values always is 'no data' ,the later item's value is always 'unknown' .

[aib]

Use ICMP template and create trigger:
when ICMP OK & agent is unreachable => send email to Administrator

[wangjf]

then ,how to express "agent is unreachable " in trigger item?

[aib]

for example:
{hostname:icmpping.max(#3)}=0

If you use Template ICMP Ping you have three triggers automatically created.
- {HOST.NAME} is unavailable by ICMP
{Template ICMP Ping:icmpping.max(#3)}=0
- Response time is too high on {HOST.NAME}
{Template ICMP Ping:icmppingsec.avg(5m)}>0.15
- Ping loss is too high on {HOST.NAME}
{Template ICMP Ping:icmppingloss.min(5m)}>20

[wangjf]

for example:
{hostname:icmpping.max(#3)}=0

If you use Template ICMP Ping you have three triggers automatically created.
- {HOST.NAME} is unavailable by ICMP
{Template ICMP Ping:icmpping.max(#3)}=0
- Response time is too high on {HOST.NAME}
{Template ICMP Ping:icmppingsec.avg(5m)}>0.15
- Ping loss is too high on {HOST.NAME}
{Template ICMP Ping:icmppingloss.min(5m)}>20

this is still a "ICMP is ok" condition, i need a "the zabbix agent can't be connected" because of a misconfigure of iptable firewall (in this situation ,the icml ping can still be ok) .

[aib]

I'm not sure that I don't say you something obvious, but Did you ever check the triggers from Templates?
For example, this one

[B]Template: Template App Zabbix Agent[/B]
Name: Zabbix agent on {HOST.NAME} is unreachable for 5 minutes
Expression: {Template App Zabbix Agent:agent.ping.nodata(5m)}=1