snmp item timeout feature?

[thresh]

Hello. Discovered weird behavoiur of item with snmp check.
Item goes for snmp oid .1.3.6.1.4.1.2021.255.30. The remote side is net-snmp-5.1.2 (no, i cant upgrade it).

For some reasons (no idea though what should be the case), some time ago snmpd responded this way [zabbix_server.log]:

011992:20070110:000033 SNMP error in packet. Reason: (noSuchName) There is no such variable name in this MIB.
011992:20070110:000033 SNMP error [(noSuchName) There is no such variable name in this MIB.]
011992:20070110:000033 Parameter [platform_idle_time] is not supported by agent on host [spider] Old status [0]
011992:20070110:000033 SNMP error in packet. Reason: (noSuchName) There is no such variable name in this MIB.
011992:20070110:000033 SNMP error [(noSuchName) There is no such variable name in this MIB.]
011992:20070110:001033 SNMP error in packet. Reason: (noSuchName) There is no such variable name in this MIB.
011992:20070110:001033 SNMP error [(noSuchName) There is no such variable name in this MIB.]
011992:20070110:002033 SNMP error in packet. Reason: (noSuchName) There is no such variable name in this MIB.
011992:20070110:002033 SNMP error [(noSuchName) There is no such variable name in this MIB.]

that item is generated by snmpd with the following configuration directive:
pass .1.3.6.1.4.1.2021.255 /usr/local/bin/platform.rb

long story short, zabbix thinks that item is "not supported".

How can i force the infinite check for that kind of items forcing them to be "supported" ?

[Alexei]

Yes, go to General->Misc->Refresh unsupported. Enter time in seconds for refresh period.

You may also check the latest ZABBIX Manual (PDF) for more details.

[thresh]

apparently, it was set to 600.
when i set that item back to 'enabled', i checked that snmp oid by snmget and it was OK.