September 2005
Beginner
462 pages
12h 56m
English
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VACM
VACM is used to control access to managed objects in a MIB or MIBs. This is where the Access Control Subsystem comes into play.
The Basics
The msgFlags, msgSecurityModel, and scopedPDU fields are used by VACM for message access. Each parameter is used to determine access to managed objects. An error is returned to the sender if access is not allowed for the request type. VACM makes use of four tables for different aspects of access control. We will discuss these tables next.
Context Table
The vacmContextTable is a collection of managed objects that have access constraints which are associated with a context name. The vacmContextTable stores all available contexts. The table is indexed by a contextName, and each row in this table contains:
-
vacmContextName A textual name for the context
Security to Group Table
The vacmSecurityToGroupTable is used to store group information. A group is made up of zero or more securityModel and securityName combinations. This combination defines what managed objects can be accessed. The table itself is indexed by a securityModel and securityName. The table contains rows made up of the following columns:
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vacmSecurityModel The security model in use—e.g., USM.
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vacmSecurityName In the case of the USM,
securityNameanduserNameare identical.-
vacmGroupName A textual name for the group to which this table entry belongs.
Access Table
The vacmAccessTable is used to store the access rights defined for groups. This table is indexed by a groupName, contextPrefix ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.