Mib Access Control - Extreme Networks ExtremeWare 7.2e Installation And User Manual

Managing the Switch
• SNMPv2c—community strings based security
• SNMPv3—USM security
The default is User-Based Security Model (USM). You can select the security model based on the
network manager in your network.
The three security levels supported by USM are:
• noAuthnoPriv—No authentication, no privacy. This is the case with existing SNMPv1/v2c agents.
• AuthnoPriv—Authentication, no privacy. Messages are tested only for authentication.
• AuthPriv—Authentication, privacy. This represents the highest level of security and requires every
message exchange to pass the authentication and encryption tests.
When a user is created, an authentication method is selected, and the authentication and privacy
passwords or keys are entered.
When MD5 authentication is specified, HMAC-MD5-96 is used to achieve authentication with a 16-octet
key, which generates an 128-bit authorization code. This code is inserted in
msgAuthenticationParameters field of SNMPv3 PDUs when the security level is specified as either
AuthnoPriv or AuthPriv. Specifying SHA authentication uses the HMAC-SHA protocol with a 20-octet
key for authentication.
For privacy, a 16-octet key is provided as input to DES-CBS encryption protocol, which generates an
encrypted PDU to be transmitted. DES uses bytes 1-7 to make a 56 bit key. This key (encrypted itself) is
placed in msgPrivacyParameters of SNMPv3 PDUs when the security level is specified as AuthPriv.

MIB Access Control

SNMPv3 provides a fine-grained mechanism for defining which parts of the MIB can be accessed. This
is referred to as the View-Based Access Control Model (VACM).
MIB views represent the basic building blocks of VACM. They are used to define a subset of the
information in the MIB. Access to read, to write, and to generate notifications is based on the
relationship between a MIB view and an access group. The users of the access group can then read,
write, or receive notifications from the part of the MIB defined in the MIB view as configured in the
access group.
A view name, a MIB subtree/mask, and an inclusion or exclusion define every MIB view. For example,
there is a System group defined under the MIB-2 tree. The Object Identifier (OID) for MIB-2 is 1.3.6.1.2,
and the System group is defined as MIB-2.1.1, or directly as 1.3.6.1.2.1.1.
To define a MIB view which includes only the System group, use the following subtree/mask
combination:
1.3.6.1.2.1.1 / 1.1.1.1.1.1.1.0
The mask can also be expressed in hex notation (this is used for the ExtremeWare CLI):
1.3.6.1.2.1.1 / fe
60 ExtremeWare 7.2e Installation and User Guide