CustoSec:Check SNMP Free Port

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Basic Information on Check
Name of Check SNMP Standard Freeport Technical Name check_snmp_free-port
Available in Standard Number of Arguments 7
From Version ARANSEC 2 Compability All ARANSEC and CustoSec




Scope of Check

Standard check to monitor the status of a remote machine and obtain system information via SNMP (Simple Network Management Protocol). SNMP is typically supported by all IP-Network devices like Servers, Routers, Firewalls, Switches, Workstations, Printers, Cameras etc. In most cases, it has to be activated on the device. Once activated, all information provided by this device can be monitored with this check.
This check is used for monitoring OID's that deliver an integer value. A "WARNING" and a "CRITICAL"-Threshold can be entered to trigger notification.
A prefix and the units can be given as arguments, to make the output easier to read.
This check is a variant of the SNMP Standard - Check, providing an extra Argument, the port number. It works exactly like this one, but it provides the possibility to change the port number of the snmp service. In some rare cases, the snmp-service is configured to another port on a host (default port is 161). In these cases, this check can be used to obtain information via SNMP.

Requirements

For the check to work properly the following requirements must be met:

  • The check is configured as a service check on the target host that should be monitored.
  • SNMP must be activated on the target host (read only and a community name; It is also recommended to allow only the ARANSEC/CustoSec IP-Address to read SNMP information on the host). SNMP can easily be checked by starting a second session in a second browser tab and do a SNMP-Walk from ARANSEC's SNMP-Walk function (bottom entry in the left hand menu).
  • When working with OID's it might prove useful to have an explanation on individual OID's at hand. A good resource for this is i.e. the OID Repository where more information on OID's can be found.
  • The value returned from the SNMP query is expected as unsigned integer. (There is a special SNMP-Check available for returned strings).

Arguments

To configure the check, the following arguments are available:

Argument No. Argument Name Allowed Arguments Explanation Examples
Arg1 snmp-community string Community name for the SNMP agent. It is strongly recommended to change the default community on most systems from "public" to something like "aransec".
Must be entered or check cannot find OID.
custosec
Arg2 port string Port number of the snmp-service on the particular host.
Must be entered or check cannot find OID.
custosec
Arg3 OID string OID: Object identifier(s) or SNMP variable(s) that are to be monitored. Those can be obtained either by doing a SNMP-Walk on the target system or search within MIB-Databases.
Must be entered or check will time out and come back with a long description of options.
It is possible to enter multiple OID's separated by a comma or a space (Internal spaces must be quoted with " "). The check will then return the values for each single OID.
hrStorageUsed.1 | 1.3.6.1.2.1.25.2.3.1.6.1
Arg4 warn integer Warning threshold range(s). Unit of measure, even though not to be entered here, must be the same as the one delivered by the OID (See the Notes at the end).
Several values/ranges can be given, when checking multiple OID's and they have to be separated with commas
5000000
5000000,7000000,4000000
Arg5 crit integer Critical threshold range(s). Unit of measure, even though not to be entered here, must be the same as the one delivered by the OID. (See the Notes at the end).
Several values/ranges can be given, when checking multiple OID's and they have to be separated with commas
7000000
7000000,10000000,6000000
Arg6 pref string Optional: Prefix label for output. Used
Arg7 unit string Optional: Units label(s) for output data pieces

Notes

Besides the 2nd argument, the check is the same as the SNMP Standard - Check. Further information and examples can be found there.