This is Bavaria, Germany!
You can check out a lot of values by SNMP. You have to install an snmp-daemon
on your pc which supplies you with snmp-data. This is possible
in Linux, Windows and Vmware ESX too!
I a lot of devices there is already an snmpd installed, for example in
network-switches. These devices are called managable and usually
cost more money than simpler devices.
Dealing with SNMP is dealing with long numbers looking like this: .1.3.6.1.4.1.232.6.2.9.3.1.4.0.1
Nobody know what this long number means. You can compare it with a directory structure which is not made by names but by numbers. There are textfiles which declare what these numbers mean. See this example from the file cpqhlth.mib (this means Compaq Health MIB)
-- The compaq enterprise (1.3.6.1.4.1.232)
-- cpqHealth Group (1.3.6.1.4.1.232.6)
-- cpqHeComponent Group (1.3.6.1.4.1.232.6.2)
-- cpqHeFltTolPowerSupply Group (1.3.6.1.4.1.232.6.2.9)
-- cpqHeFltTolPowerSupplyTable (1.3.6.1.4.1.232.6.2.9.3)
[...]
CpqHeFltTolPowerSupplyEntry ::= SEQUENCE {
cpqHeFltTolPowerSupplyChassis INTEGER,
cpqHeFltTolPowerSupplyBay INTEGER,
cpqHeFltTolPowerSupplyPresent INTEGER,
cpqHeFltTolPowerSupplyCondition INTEGER,
cpqHeFltTolPowerSupplyStatus INTEGER,
cpqHeFltTolPowerSupplyMainVoltage INTEGER,
cpqHeFltTolPowerSupplyCapacityUsed INTEGER,
cpqHeFltTolPowerSupplyCapacityMaximum INTEGER,
cpqHeFltTolPowerSupplyRedundant INTEGER,
cpqHeFltTolPowerSupplyModel DisplayString,
cpqHeFltTolPowerSupplySerialNumber DisplayString,
cpqHeFltTolPowerSupplyAutoRev OCTET STRING,
cpqHeFltTolPowerSupplyHotPlug INTEGER,
cpqHeFltTolPowerSupplyFirmwareRev DisplayString,
cpqHeFltTolPowerSupplyHwLocation DisplayString,
cpqHeFltTolPowerSupplySparePartNum DisplayString,
cpqHeFltTolPowerSupplyRedundantPartner INTEGER
}
[...]
cpqHeFltTolPowerSupplyCondition OBJECT-TYPE
SYNTAX INTEGER {
other(1),
ok(2),
degraded(3),
failed(4)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The condition of the power supply.
This value will be one of the following:
other(1)
The status could not be determined or not present.
ok(2)
The power supply is operating normally.
degraded(3)
A temperature sensor, fan or other power supply component is
outside of normal operating range.
failed(4)
A power supply component detects a condition that could
permanently damage the system."
::= { cpqHeFltTolPowerSupplyEntry 4 }
You don't have to understand this completely. In this example browse with your MIB-browser the oid mentioned in the first lines .1.3.6.1.4.1.232.6.2.9.3 and try to interpret the values you get together with the MIB-file.
MIB-files help you to understand which questions you can ask to your device. There are common MIB-files where there are values nearly every device can interpret. But there are also special MIB-files for special devices (Network attached storage, network filer, temperature devices etc.). I will give you some hints where to find these files:
You have to have managable device. For example a network-switch. The device itself has an ip-address and a community name (which is simply a password to get values from the device, the default value is "public").
Just take a MIB-Browser (see below), navigate to your device-ip (don't take dns-names, I don't know why they don't work so often with this programs) and get subtree of: .1.3.6.1.2.1.1 which gives you a system-description.
There is a lot of bad software in the internet. Most good tools must be bought and costs more than 200 $. See my suggestions: