Check if OID exists

[ray.holtz]

I'd like to do a check on my Juniper SRX firewalls to see what the static route is. I know the OID is .1.3.6.1.4.1.2636.3.38.1.1.1.0.0.0.0.0.0.0.0.0.x.x.x.x (where x.x.x.x is my default route IP).

When I run a check_snmp on that OID, it comes back as OK. If I change the IP in the check to simulate the actual static route changing, the check comes back with:

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External command error: Error in packet
Reason: (noSuchName) There is no such variable name in this MIB.
Failed object: iso.3.6.1.4.1.2636.3.38.1.1.1.0.0.0.0.0.0.0.0.0.x.x.x.x

which is status:unknown

If I add -w 0 -c 0 to the command, it says No valid data returned.

Is there a way to have this give me a Critical status so I get an notification?

Thanks,
Ray

[rkennedy]

It sounds like it can't find the OID, what is the result if you run a SNMPwalk against the machine for that OID?

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snmpwalk -c nagiosprivate -v 2c ip .1.3.6.1.4.1.2636.3.38.1.1.1.0.0.0.0.0.0.0.0.0.x.x.x.x

(adjust as needed)

[ray.holtz]

I actually want it to not find the OID. In the case that the default static route on the firewall has changed, I would like to get a critical notification.

If it can find the OID, all is good and static route is good and the status should be OK
If it can not find the OID, that means the static route has changed, and I'd like it to be Critical instead of Unknown.

Thanks,
Ray

[rkennedy]

Ah, I misunderstood at first. I was wondering how a dynamic OID would change within as well. Anyways, you'll want to use the negate plugin.

Here's a working check -

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[root@localhost libexec]# ./check_snmp -H 192.168.5.41 -C nagiosprivate -o IF-MIB::ifIndex.1
SNMP OK - 1 | IF-MIB::ifIndex.1=1
[root@localhost libexec]# echo $?
0

Now, changing it to an invalid MIB -

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[root@localhost libexec]# ./check_snmp -H 192.168.5.41 -C nagiosprivate -o IF-MIB::ifIndex.0
External command error: IF-MIB::ifIndex.0: Unknown Object Identifier (Index out of range: 0 (ifIndex))
[root@localhost libexec]# echo $?
3

Now, run it through negate. I'm using -u OK to change UNKNOWN -> OK.

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[root@localhost libexec]# ./negate -u OK ./check_snmp -H 192.168.5.41 -C nagiosprivate -o IF-MIB::ifIndex.0
External command error: IF-MIB::ifIndex.0: Unknown Object Identifier (Index out of range: 0 (ifIndex))
[root@localhost libexec]# echo $?
0

So, for you, we need to use -u CRITICAL.

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[root@localhost libexec]# ./negate -u CRITICAL ./check_snmp -H 192.168.5.41 -C nagiosprivate -o IF-MIB::ifIndex.0
External command error: IF-MIB::ifIndex.0: Unknown Object Identifier (Index out of range: 0 (ifIndex))
[root@localhost libexec]# echo $?
2

Hopefully that helps illustrate it for you, let us know if you have any questions.

[ray.holtz]

Thanks, that might help. But how do I get that to work in a service check? I have the service defined as:

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define service{
        hosts                                   host
        servicegroups                           ALL_DefaultRoutes
        service_description                     SRX Default Route
        contact_groups                          Network
        check_command                           check_snmp!-C community -o .1.3.6.1.4.1.2636.3.38.1.1.1.0.0.0.0.0.0.0.0.0.x.x.x.x
        use                                     service
        }

and the command as:

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define command{
        command_name    check_snmp
        command_line    $USER1$/check_snmp -H $HOSTADDRESS$ $ARG1$
        }

Would the command be:

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define command{
        command_name    check_snmp
        command_line    $USER1$/negate -u CRITICAL $USER1$/check_snmp -H $HOSTADDRESS$ $ARG1$
        }

[rkennedy]

Yep, I believe that will work for you after reviewing your command definition. Are you running into issues?

[ray.holtz]

Thanks a lot @rkennedy.

That negate command works great!

[rkennedy]

Awesome! It's pretty handy for things like this that you expect to fail, but know it's not critical.

Are we good to mark this thread as resolved?