"Zabbix agent" checks NOK, "Zabbix agent (active)" checks OK

[herta]

Environment:
- zabbix server OS: ubuntu 12.04.1
- windows server OS: windows 2008 R2 64-bit
- zabbix version: 2.0.4

We have two servers in our DMZ which are monitored by zabbix: one linux and one windows. Both have the same configuration on the firewall.

For some reason, for the windows server, zabbix reports the "Zabbix agent on <windows-server> unreachable for 5 minutes". Yet all the items of type "Zabbix Agent (active)" work just fine. Items of type "Zabbix Agent" are marked as 'Last check - Never'.

In the Configuration screen, the zabbix agent monitoring icon is red and displays the message "Get value from agent failed: ZBX_TCP_READ() failed: [104] Connection reset by peer".

I disabled the firewall on the windows server itself to be sure it had no influence. On the command line (bash shell), fping from the zabbix server to the windows server also works fine.

The linux server has no problems.

Any ideas, anyone?

[herta]

dns in dmz was configured incorrectly

Just stumbled across the root cause: the DMZ DNS server returned the wrong address for the zabbix server.

Problem solved

Sorry about this.