snmpvacm(1)
NAME
snmpvacm - creates and maintains SNMPv3 View-based Access Control entries on a network entity
SYNOPSIS
snmpvacm [COMMON OPTIONS] AGENT createSec2Group MODEL SECURITYNAME GROUPNAME snmpvacm [COMMON OPTIONS] AGENT deleteSec2Group MODEL SECURITYNAME snmpvacm [COMMON OPTIONS] AGENT createView [-Ce] NAME SUBTREE MASK snmpvacm [COMMON OPTIONS] AGENT deleteView NAME SUBTREE snmpvacm [COMMON OPTIONS] AGENT createAccess GROUPNAME [CONTEXTPREFIX] MODEL LEVEL CONTEXTMATCH READVIEW WRITEVIEW NOTIFYVIEW snmpvacm [COMMON OPTIONS] AGENT deleteAccess GROUPNAME [CONTEXTPREFIX] MODEL LEVEL snmpvacm [COMMON OPTIONS] AGENT createAuth GROUPNAME [CONTEXTPREFIX] MODEL LEVEL AUTHTYPE CONTEXTMATCH VIEW snmpvacm [COMMON OPTIONS] AGENT deleteAuth GROUPNAME [CONTEXTPREFIX] MODEL LEVEL AUTHTYPE
DESCRIPTION
snmpvacm is an SNMP application that can be used to do simple maintenance on the View-based Control Module (VACM) tables of an SNMP agent. The SNMPv3 VACM specifications (see RFC2575) define assorted tables to specify groups of users, MIB views, and authorised access settings. These snmpvacm commands effectively create or delete rows in the appropriate one of these tables, and match the equivalent configure directives which are documented in the snmpd.conf(5) man page. A fuller explanation of how these operate can be found in the project FAQ.
SUB-COMMANDS
createSec2Group MODEL SECURITYNAME GROUPNAME
Create an entry in the SNMPv3 security name to group table. This table
allows a single access control entry to be applied to a number of users
(or 'principals'), and is indexed by the security model and security
name values.
MODEL
An integer representing the security model, taking one of the
following values:
1 - reserved for SNMPv1
2 - reserved for SNMPv2c
3 - User-based Security Model (USM)
SECURITYNAME
A string representing the security name for a principal
(represented in a security-model-independent format). For USM-
based requests, the security name is the same as the username.
GROUPNAME
A string identifying the group that this entry (i.e. security
name/model pair) should belong to. This group name will then be
referenced in the access table (see createAccess below).
deleteSec2Group MODEL SECURITYNAME
Delete an entry from the SNMPv3 security name to group table, thus
removing access control settings for the given principal. The entry to
be removed is indexed by the MODEL and SECURITYNAME values, which
should match those used in the corresponding createSec2Group command
(or equivalent).
createView [-Ce] NAME SUBTREE MASK
Create an entry in the SNMPv3 MIB view table. A MIB view consists of a
family of view subtrees which may be individually included in or
(occasionally) excluded from the view. Each view subtree is defined by
a combination of an OID subtree together with a bit string mask. The
view table is indexed by the view name and subtree OID values.
[-Ce]
An optional flag to indicate that this view subtree should be
excluded from the named view. If not specified, the default is
to include the subtree in the view. When constructing a view
from a mixture of included and excluded subtrees, the excluded
subtrees should be defined first - particularly if the named
view is already referenced in one or more access entries.
NAME
A string identifying a particular MIB view, of which this OID
subtree/mask forms part (possibly the only part).
SUBTREE
The OID defining the root of the subtree to add to (or exclude
from) the named view.
MASK
A bit mask indicating which sub-identifiers of the associated
subtree OID should be regarded as significant.
deleteView NAME SUBTREE
Delete an entry from the SNMPv3 view table, thus removing the subtree
from the given MIB view. Removing the final (or only) subtree will
result in the deletion of the view. The entry to be removed is indexed
by the NAME and SUBTREE values, which should match those used in the
corresponding createView command (or equivalent).
When removing subtrees from a mixed view (i.e. containing both included
and excluded subtrees), the included subtrees should be removed first.
createAccess GROUPNAME [CONTEXTPREFIX] MODEL LEVEL CONTEXTMATCH READVIEW
WRITEVIEW NOTIFYVIEW
Create an entry in the SNMPv3 access table, thus allowing a certain
level of access to particular MIB views for the principals in the
specified group (given suitable security model and levels in the
request). The access table is indexed by the group name, context
prefix, security model and security level values.
GROUPNAME
The name of the group that this access entry applies to (as set
up by a createSec2Group command, or equivalent)
CONTEXTPREFIX
A string representing a context name (or collection of context
names) which this access entry applies to. The interpretation
of this string depends on the value of the CONTEXTMATCH field
(see below).
If omitted, this will default to the null context "".
MODEL
An integer representing the security model, taking one of the
following values:
1 - reserved for SNMPv1
2 - reserved for SNMPv2c
3 - User-based Security Model (USM)
LEVEL
An integer representing the minimal security level, taking one
of the following values:
1 - noAuthNoPriv
2 - authNoPriv
3 - authPriv
This access entry will be applied to requests of this level or
higher (where authPriv is higher than authNoPriv which is in
turn higher than noAuthNoPriv).
CONTEXTMATCH
Indicates how to interpret the CONTEXTPREFIX value. If this
field has the value '1' (representing 'exact') then the context
name of a request must match the CONTEXTPREFIX value exactly for
this access entry to be applicable to that request.
If this field has the value '2' (representing 'prefix') then the
initial substring of the context name of a request must match
the CONTEXTPREFIX value for this access entry to be applicable
to that request. This provides a simple form of wildcarding.
READVIEW
The name of the MIB view (as set up by createView or equivalent)
defining the MIB objects for which this request may request the
current values.
If there is no view with this name, then read access is not
granted.
WRITEVIEW
The name of the MIB view (as set up by createView or equivalent)
defining the MIB objects for which this request may potentially
SET new values.
If there is no view with this name, then read access is not
granted.
NOTIFYVIEW
The name of the MIB view (as set up by createView or equivalent)
defining the MIB objects which may be included in notification
request.
Note that this aspect of access control is not currently
supported.
deleteAccess GROUPNAME [CONTEXTPREFIX] MODEL LEVEL
Delete an entry from the SNMPv3 access table, thus removing the
specified access control settings. The entry to be removed is indexed
by the group name, context prefix, security model and security level
values, which should match those used in the corresponding createAccess
command (or equivalent).
createAuth GROUPNAME [CONTEXTPREFIX] MODEL LEVEL AUTHTYPE CONTEXTMATCH VIEW
Create an entry in the Net-SNMP extension to the standard access table,
thus allowing a certain type of access to the MIB view for the
principals in the specified group. The interpretation of GROUPNAME,
CONTEXTPREFIX, MODEL, LEVEL and CONTEXTMATCH are the same as for the
createAccess directive. The extension access table is indexed by the
group name, context prefix, security model, security level and authtype
values.
AUTHTYPE
The style of access that this entry should be applied to. See
snmpd.conf(5) and snmptrapd.conf(5) for details of valid tokens.
VIEW
The name of the MIB view (as set up by createView or equivalent)
defining the MIB objects for which this style of access is
authorized.
deleteAuth GROUPNAME [CONTEXTPREFIX] MODEL LEVEL AUTHTYPE
Delete an entry from the extension access table, thus removing the
specified access control settings. The entry to be removed is indexed
by the group name, context prefix, security model, security level and
authtype values, which should match those used in the corresponding
createAuth command (or equivalent).
Note that snmpget REQUIRES an argument specifying the agent to query
as described in the .I snmpcmd(1) manual page.
EXAMPLES
Given a pre-existing user dave (which could be set up using the snmpusm(1) command), we could configure full read-write access to the whole OID tree using the commands: snmpvacm localhost createSec2Group 3 dave RWGroup snmpvacm localhost createView all .1 80 snmpvacm localhost createAccess RWGroup 3 1 1 all all none This creates a new security group named "RWGroup" containing the SNMPv3 user "dave", a new view "all" containing the full OID tree based on .iso(1) , and then allows those users in the group "RWGroup" (i.e. "dave") both read- and write-access to the view "all" (i.e. the full OID tree) when using authenticated SNMPv3 requests. As a second example, we could set up read-only access to a portion of the OID tree using the commands: snmpvacm localhost createSec2Group 3 wes ROGroup snmpvacm localhost createView sysView system fe snmpvacm localhost createAccess ROGroup 3 0 1 sysView none none This creates a new security group named "ROGroup" containing the (pre- existing) user "wes", a new view "sysView" containing just the OID tree based on .iso(1).org(3).dod(6).inet(1).mgmt(2).mib-2(1).system(1) , and then allows those users in the group "ROGroup" (i.e. "wes") read- access, but not write-access to the view "sysView" (i.e. the system group).
EXIT STATUS
The following exit values are returned: 0 - Successful completion 1 - A usage syntax error (which displays a suitable usage message) or a request timeout. 2 - An error occurred while executing the command (which also displays a suitable error message).
LIMITATIONS
This utility does not support the configuration of new community strings, so is only of use for setting up new access control for SNMPv3 requests. It can be used to amend the access settings for existing community strings, but not to set up new ones. The use of numeric parameters for secLevel and contextMatch parameters is less than intuitive. These commands do not provide the full flexibility of the equivalent config file directives. There is (currently) no equivalent to the one-shot configure directives rouser and rwuser.
SEE ALSO
snmpcmd(1), snmpusm(1), snmpd.conf(5), snmp.conf(5), RFC 2575, Net-SNMP project FAQ
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
