SNMP monitoring of a Dell switch: snmpwalk succeds but check_snmp fails.

[Max]

On Thu, Jan 29, 2009 at 7:56 PM, Rahul Nabar <rpnabar at gmail.com> wrote:
> I was trying to monitor my Dell Power Connect Switch via nagios. I used the
> default templates and have this check_command in my switch.cfg:
> check_command           check_snmp!-C public -o ifOperStatus.1 -r 1 -m
> RFC1213-MIB
>
> Unfortunately the web-interface shows: "SNMP CRITICAL - *down(2)* "
>
> Now I tried a naked SNMP query on this switch:
>
> snmpwalk -v1 -c public switch3 -m ALL.1 > /tmp/switch3.snmp.log
>
> The switch does respond with reams of output! But I am not really sure what
> I should be looking for in there. I tried grepping on " ifOperStatus.1" but
> that is not to be found.
>
> Any other suggestions how to monitor this recalcitrant Dell switch?

The OID that maps to ifOperStatus from RFC1213-MIB is 1.3.6.1.2.1.2.2.1.8

So grep for

1.3.6.1.2.1.2.2.1.8.1

if the interface you want to look at is indeed at index 1 :).  When
running a check within Nagios, for performance reasons it generally is
preferable to document what the name of the OID is in the service
comments and use the dotted notation in the check .. as otherwise the
command, which I think just cals a Net-SNMP command, has to then load
and parse the whole MIB file just to turn your single OID name into
the numeric representation.

If you are just running this for one port on one switch, then loading
the MIB is no biggie, if you plan to monitor hundreds or thousands of
ports, would be better to use the numeric form of the OID and run an
ePN plugin using the perl Net::SNMP or NSNMP library or a plugin that
implements the C Net-SNMP libraries directly

To view the mappings of OID descriptions to OIDs from the CLI you can
use the Net-SNMP snmptranslate tool:

snmptranslate -Tz -m RFC1213-MIB

Gives a nice output format .. e.g. first 20 or so lines from the above:

"org"                   "1.3"
"dod"                   "1.3.6"
"internet"                      "1.3.6.1"
"directory"                     "1.3.6.1.1"
"mgmt"                  "1.3.6.1.2"
"mib-2"                 "1.3.6.1.2.1"
"system"                        "1.3.6.1.2.1.1"
"sysDescr"                      "1.3.6.1.2.1.1.1"
"sysObjectID"                   "1.3.6.1.2.1.1.2"
"sysUpTime"                     "1.3.6.1.2.1.1.3"
"sysContact"                    "1.3.6.1.2.1.1.4"
"sysName"                       "1.3.6.1.2.1.1.5"
"sysLocation"                   "1.3.6.1.2.1.1.6"
"sysServices"                   "1.3.6.1.2.1.1.7"
"sysORLastChange"                       "1.3.6.1.2.1.1.8"
"sysORTable"                    "1.3.6.1.2.1.1.9"
"sysOREntry"                    "1.3.6.1.2.1.1.9.1"


- Max

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