How to choose OID's for custom SNMP queries?

[Lojak]

Hi all,

I've Google'd without much success, so I'll take a stab here. I want to know how to choose custom OID's for SNMP queries that will be returned by an application. Generally speaking, I've had some success, but I don't understand the best method to choose a range of OID's that will not conflict with others. FWIW, I'm using FreeBSD 4.10 on the machine in question.

I'd appreciate any pointers.

-- Stephen.

[duckhead]

There is a location that's defined for custom SNMP OID's. It's under the enterprises sub-tree AKA .iso.org.dod.internet.private.enterprises , or .1.3.6.1.4.1 The next number under there is assigned to organizations, like NetApp Cisco, and others. Then they can build their custom trees under there.

I don't know if there's any provision in the RFC's to provde for an enterprises sub-tree that's guaranteed not to be assigned. If there is, I'd love to know what it is for myself.

If there isn't, your best bet is to get your own number assigned. The IANA is responsible for that. You can request a number here: http://www.iana.org/cgi-bin/enterprise.pl

[Lojak]

Thanks for the info..

I don't need numbers actually assigned, per se. To be more specific, I've got some stats I want Cacti to graph, and those stats are generated by scripts I run on a server. Choosing OID's arbitrarily has proven to be a bad decision, because often data is returned that relates to something else entirely, rather than the data I want returned. What I need to know is how to determine if I can find some dummy OID range that can be used for that purpose locally, but not applied across the board.

-- Stephen.

[duckhead]

OK, let me try this again. Please understand that the wonderful people that wrote SMI know exactly what they're talking about. As such, they've told us exactly how to accomplish this. The only way to get a guaranteed empty spot in the tree is to do the following:

1. Use the enterprises sub-tree. Someone owns all of the other OID's, so picking one of those will only lead to grief. That's why the standard requires you to use this OID.

2. Use an OID under enterprises that has been assigned to you. All other OID's are either owned by someone else, or will be. That's why the standard requires that you be assigned one.

I don't believe that I ever gave you a list of assigned numbers, the link above is to the form that let's you register for your own OID under the enterprises sub-tree. Although it does have a link to the list of assigned numbers. And, you should review this list to make sure that your company doesn't already have on OID assigned. If you don't see the form try scrolling down. If you're getting some other result, let me know and I'll confirm the link.

[Lojak]

Thanks very much! I really appreciate it!

-- Stephen

[nerdality]

I needed to poll individual CPU stats from a 6-processor SMP machine, so I added:

exec cpu0.user /path/to/script

in the snmpd.conf file, and the results show up in:
ext.Output.1

In the enterprise tree.