SNMPVACM(1)                                                 Net-SNMP                                                 SNMPVACM(1)



NAME
       snmpvacm - creates and maintains SNMPv3 View-based Access Control entries on a network entity

SYNOPSIS
       snmpvacm [COMMON OPTIONS] createSec2Group MODEL SECURITYNAME  GROUPNAME
       snmpvacm [COMMON OPTIONS] deleteSec2Group MODEL SECURITYNAME
       snmpvacm [COMMON OPTIONS] createView [-Ce] NAME SUBTREE MASK
       snmpvacm [COMMON OPTIONS] deleteView NAME SUBTREE
       snmpvacm [COMMON OPTIONS] createAccess GROUPNAME [CONTEXTPREFIX] MODEL LEVEL CONTEXTMATCH READVIEW WRITEVIEW NOTIFYVIEW
       snmpvacm [COMMON OPTIONS] deleteAccess GROUPNAME [CONTEXTPREFIX] MODEL LEVEL
       snmpvacm [COMMON OPTIONS] createAuth GROUPNAME [CONTEXTPREFIX] MODEL LEVEL AUTHTYPE CONTEXTMATCH VIEW
       snmpvacm [COMMON OPTIONS] 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 princi-
       pal.  The entry to be removed is indexed by the MODEL and SECURITYNAME values, which should match those used in the  cor-
       responding 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 val-
       ues, 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 prin-
       cipals 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 CON-
       TEXTMATCH are the same as for the createAccess directive.  The extension access table is indexed by the group name,  con-
       text 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).


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" contain-
       ing  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



4th Berkeley Distribution                                  30 May 2003                                               SNMPVACM(1)