Connectivity Guide

Management Information Base Object Identifiers
Each data class within a Management Information Base (MIB) is defined by an Object Identifier (OID). OIDs are unique across all
MIBs. An OID consists of a series of digits separated by periods. The OID functions in a similar fashion to a phone number. The
phone number 011-512-471-0000 uniquely identifies a single phone. The phone number can be broken down into a number of
components to uniquely identify a phone. The first component, 011, is the country code for the United States. The second
component, 512, identifies the area code for central Texas. The third component, 471, is the phone exchange for a large state
university in the city of Austin. The final component, 0000, is the main switchboard.
There are two main differences between the phone number example and an actual OID. The first difference is that there are
many more components in an OID, up to 128. The combination of these components is called an OID prefix. The second
difference is that OIDs support the concept of indexes or keys. The OID prefix specifies the data class but does not specify an
instance of the data within the class. Indexes can be used to identify the instances of a data class. These indexes are referred to
as the OID suffix.
The assignment of values for each OID prefix component can be illustrated by using a tree structure. The following is an
example of an OID assignment:
Table 13. ROOT
CCITT(0)
ISO(1)
ORG(3)
DOD(6)
INTERNET(1)
MGMT(2)
MIB(1)
EXPERIMENTAL
(3)
PRIVATE(4)
ENTERPRISES(1
)
DELL (674)
SNMPv2(6)
In the preceding example, the OID prefix for the Dell enterprise would be 1.3.6.1.4.1.674.
The numbers in boldface type show the categories and numbers that apply to Server Administrator. All Server Administrator-
defined OIDs consist of 1.3.6.1.4.1.674 followed by additional component values.
SNMP Security
SNMP version 1 has a very limited security mechanism. SNMP agents support the use of a community string, which is
configured at each SNMP agent and is passed as a part of all SNMP request messages. There is no verification that the
requester is actually a member of the specified community. As most system and network management data is not confidential,
this limited security is acceptable for Get types of requests. On the other hand, this security is not acceptable for Set types of
operations where an SNMP request could power off a system, reconfigure a redundant array of independent disks (RAID) card,
and so on. Dell has chosen not to support SNMP Set operations for this reason.
NOTE:
The default SNMP agent configuration usually includes a SNMP community name such as public. For security
reasons, change the SNMP community names from their default values. For information about changing SNMP community
names, see the Dell OpenManage Server Administrator User’s Guide available on the Dell Support website at dell.com/
openmanagemanuals.
NOTE: As of iDRAC7 firmware release r1.30.30, iDRAC7 supports SNMP query operations (GET, GETNEXT, GETBULK) via
the SNMPv3 protocol, in addition to supporting query operations via the SNMP v1 and SNMP v2c protocols. More
specifically, iDRAC7 now supports the SNMP User Security Model (USM).
14 Introduction