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<chapter>
  <header>
    <copyright>
      <year>1997</year><year>2011</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
      compliance with the License. You should have received a copy of the
      Erlang Public License along with this software. If not, it can be
      retrieved online at http://www.erlang.org/.
    
      Software distributed under the License is distributed on an "AS IS"
      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
      the License for the specific language governing rights and limitations
      under the License.
    
    </legalnotice>

    <title>Definition of Agent Configuration Files</title>
    <prepared></prepared>
    <responsible></responsible>
    <docno></docno>
    <approved></approved>
    <checked></checked>
    <date></date>
    <rev></rev>
    <file>snmp_agent_config_files.xml</file>
  </header>
  <p>All configuration data must be included in configuration files
    that are located in the configuration directory. The name of this
    directory is given in the <c>config_dir</c> configuration
    parameter.  These files are read at start-up, and are used to
    initialize the SNMPv2-MIB or STANDARD-MIB, SNMP-FRAMEWORK-MIB,
    SNMP-MPD-MIB, SNMP-VIEW-BASED-ACM-MIB, SNMP-COMMUNITY-MIB,
    SNMP-USER-BASED-SM-MIB, SNMP-TARGET-MIB and SNMP-NOTIFICATION-MIB
    (refer to the <seealso marker="snmp_agent_funct_descr#management">Management of the Agent</seealso> for a description of the MIBs). </p>
  <p>The files are: </p>
  <list type="bulleted">
    <item>
      <p><c>agent.conf</c>: see 
        <seealso marker="#agent_information">Agent Information</seealso></p>
    </item>
    <item>
      <p><c>standard.conf</c>: see 
        <seealso marker="#system_information">System Information</seealso></p>
    </item>
    <item>
      <p><c>context.conf</c>: see 
        <seealso marker="#context">Contexts</seealso></p>
    </item>
    <item>
      <p><c>community.conf</c>: see 
        <seealso marker="#community">Communities</seealso></p>
    </item>
    <item>
      <p><c>target_addr.conf</c>: see 
        <seealso marker="#target_addr">Target Address Definitions</seealso></p>
    </item>
    <item>
      <p><c>target_params.conf</c>: see 
        <seealso marker="#target_params">Target Parameters Definitions</seealso></p>
    </item>
    <item>
      <p><c>vacm.conf</c>: see 
        <seealso marker="#vacm">MIB Views for VACM</seealso></p>
    </item>
    <item>
      <p><c>usm.conf</c>: see 
        <seealso marker="#usm">Security data for USM</seealso></p>
    </item>
    <item>
      <p><c>notify.conf</c>: see 
        <seealso marker="#notify">Notify Definitions</seealso></p>
    </item>
  </list>
  <p>The directory where the configuration files are found is given as
    a parameter to the agent. </p>
  <p>The entry format in all files are Erlang terms, separated by a
    '<em>.</em>' and a <em>newline</em>. In the following sections, the
    formats of these terms are described. Comments may be specified as
    ordinary Erlang comments. </p>
  <p>Syntax errors in these files are discovered and reported with the
    function <c>config_err/2</c> of the error report module at start-up. </p>

  <section>
    <marker id="agent_information"></marker>
    <title>Agent Information</title>
    <p>The agent information should be stored in a file called
      <c>agent.conf</c>.
      </p>
    <p>Each entry is a tuple of size two:
      </p>
    <p><c>{AgentVariable, Value}.</c></p>
    <list type="bulleted">
      <item><c>AgentVariable</c> is one of the variables is
       SNMP-FRAMEWORK-MIB or one of the internal variables
      <c>intAgentUDPPort</c>, which defines which UDP port the agent
       listens to, or <c>intAgentIpAddress</c>, which defines the IP
       address of the agent.
      </item>
      <item><c>Value</c> is the value for the variable.
      </item>
    </list>
    <p>The following example shows a <c>agent.conf</c> file: 
      </p>
    <pre>
{intAgentUDPPort, 4000}.
{intAgentIpAddress,[141,213,11,24]}.
{snmpEngineID, "mbj's engine"}.
{snmpEngineMaxPacketSize, 484}.
    </pre>
    <p>The value of <c>snmpEngineID</c> is a string, which for a 
      deployed agent should have a very specific structure. See
      RFC 2271/2571 for details.
      </p>
  </section>

  <section>
    <marker id="context"></marker>
    <title>Contexts</title>
    <p>The context information should be stored in a file called
      <c>context.conf</c>.  The default context <c>""</c>
      need not be present.
      </p>
    <p>Each row defines a context in the agent.  This information is
      used in the table <c>vacmContextTable</c> in the
      SNMP-VIEW-BASED-ACM-MIB.
      </p>
    <p>Each entry is a term:
      </p>
    <p><c>ContextName.</c></p>
    <list type="bulleted">
      <item><c>ContextName</c> is a string.
      </item>
    </list>
  </section>

  <section>
    <marker id="system_information"></marker>
    <title>System Information</title>
    <p>The system information should be stored in a file called
      <c>standard.conf</c>.
      </p>
    <p>Each entry is a tuple of size two:
      </p>
    <p><c>{SystemVariable, Value}.</c></p>
    <list type="bulleted">
      <item><c>SystemVariable</c> is one of the variables in the
       system group, or <c>snmpEnableAuthenTraps</c>.
      </item>
      <item><c>Value</c> is the value for the variable.
      </item>
    </list>
    <p>The following example shows a valid <c>standard.conf</c> file: 
      </p>
    <pre>
{sysDescr, "Erlang SNMP agent"}.
{sysObjectID, [1,2,3]}.
{sysContact, "(mbj,eklas)@erlang.ericsson.se"}.
{sysName, "test"}.
{sysServices, 72}.
{snmpEnableAuthenTraps, enabled}.
    </pre>
    <p>A value must be provided for all variables, which lack default
      values in the MIB.
      </p>
  </section>

  <section>
    <marker id="community"></marker>
    <title>Communities</title>
    <p>The community information should be stored in a file called
      <c>community.conf</c>.  It must be present if the agent is
      configured for SNMPv1 or SNMPv2c.
      </p>
    <p>An SNMP <em>community</em> is a relationship between an SNMP
    agent and a set of SNMP managers that defines authentication, access 
    control and proxy characteristics. </p>
    <p>The corresponding table is <c>snmpCommunityTable</c> in the
      SNMP-COMMUNITY-MIB. </p>
    <p>Each entry is a term: </p>
    <p><c>{CommunityIndex, CommunityName, SecurityName, ContextName, TransportTag}.</c></p>
    <list type="bulleted">
      <item><c>CommunityIndex</c> is a non-empty string.
      </item>
      <item><c>CommunityName</c> is a string.
      </item>
      <item><c>SecurityName</c> is a string.
      </item>
      <item><c>ContextName</c> is a string.
      </item>
      <item><c>TransportTag</c> is a string.
      </item>
    </list>
  </section>

  <section>
    <marker id="vacm"></marker>
    <title>MIB Views for VACM</title>
    <p>The information about MIB Views for VACM should be stored in a 
      file called
      <c>vacm.conf</c>.
      </p>
    <p>The corresponding tables are <c>vacmSecurityToGroupTable</c>,
      <c>vacmAccessTable</c> and <c>vacmViewTreeFamilyTable</c> in the
      SNMP-VIEW-BASED-ACM-MIB.
      </p>
    <p>Each entry is one of the terms, one entry corresponds to one
      row in one of the tables.
      </p>
    <p><c>{vacmSecurityToGroup, SecModel, SecName, GroupName}.</c></p>
    <p><c>{vacmAccess, GroupName, Prefix, SecModel, SecLevel, Match, ReadView, WriteView, NotifyView}.</c></p>
    <p><c>{vacmViewTreeFamily, ViewIndex, ViewSubtree, ViewStatus, ViewMask}.</c></p>
    <list type="bulleted">
      <item>
        <p><c>SecModel</c> is <c>any</c>, <c>v1</c>, <c>v2c</c>, or
          <c>usm</c>.</p>
      </item>
      <item>
        <p><c>SecName</c> is a string.</p>
      </item>
      <item>
        <p><c>GroupName</c> is a string.</p>
      </item>
      <item>
        <p><c>Prefix</c> is a string.</p>
      </item>
      <item>
        <p><c>SecLevel</c> is <c>noAuthNoPriv</c>, <c>authNoPriv</c>,
          or <c>authPriv</c></p>
      </item>
      <item>
        <p><c>Match</c> is <c>prefix</c> or <c>exact</c>.</p>
      </item>
      <item>
        <p><c>ReadView</c> is a string.</p>
      </item>
      <item>
        <p><c>WriteView</c> is a string.</p>
      </item>
      <item>
        <p><c>NotifyView</c> is a string.
          </p>
      </item>
      <item>
        <p><c>ViewIndex</c> is an integer.</p>
      </item>
      <item>
        <p><c>ViewSubtree</c> is a list of integer.</p>
      </item>
      <item>
        <p><c>ViewStatus</c> is either <c>included</c> or <c>excluded</c></p>
      </item>
      <item>
        <p><c>ViewMask</c> is either <c>null</c> or a list of ones and
          zeros. Ones nominate that an exact match is used for this
          sub-identifier. Zeros are wild-cards which match any
          sub-identifier. If the mask is shorter than the sub-tree, the
          tail is regarded as all ones. <c>null</c> is shorthand for a
          mask with all ones.</p>
      </item>
    </list>
  </section>

  <section>
    <marker id="usm"></marker>
    <title>Security data for USM</title>
    <p>The information about Security data for USM should be stored in a 
      file called
      <c>usm.conf</c>, which must be present if the agent is configured
      for SNMPv3.
      </p>
    <p>The corresponding table is <c>usmUserTable</c> in the
      SNMP-USER-BASED-SM-MIB.
      </p>
    <p>Each entry is a term:
      </p>
    <p><c>{EngineID, UserName, SecName, Clone, AuthP, AuthKeyC, OwnAuthKeyC, PrivP, PrivKeyC, OwnPrivKeyC, Public, AuthKey, PrivKey}.</c></p>
    <list type="bulleted">
      <item>
        <p><c>EngineID</c> is a string.
          </p>
      </item>
      <item>
        <p><c>UserName</c> is a string.</p>
      </item>
      <item>
        <p><c>SecName</c> is a string.</p>
      </item>
      <item>
        <p><c>Clone</c> is <c>zeroDotZero</c> or a list of integers.</p>
      </item>
      <item>
        <p><c>AuthP</c> is a <c>usmNoAuthProtocol</c>,
          <c>usmHMACMD5AuthProtocol</c>, or <c>usmHMACSHAAuthProtocol</c>.</p>
      </item>
      <item>
        <p><c>AuthKeyC</c> is a string.</p>
      </item>
      <item>
        <p><c>OwnAuthKeyC</c> is a string.</p>
      </item>
      <item>
        <p><c>PrivP</c> is a <c>usmNoPrivProtocol</c>, 
          <c>usmDESPrivProtocol</c> or <c>usmAesCfb128Protocol</c>.</p>
      </item>
      <item>
        <p><c>PrivKeyC</c> is a string.</p>
      </item>
      <item>
        <p><c>OwnPrivKeyC</c> is a string.</p>
      </item>
      <item>
        <p><c>Public</c> is a string.</p>
      </item>
      <item>
        <p><c>AuthKey</c> is a list (of integer).  This is the User's secret
          localized authentication key.  It is not visible in the MIB.  The length
          of this key needs to be 16 if <c>usmHMACMD5AuthProtocol</c> is used, and 
          20 if <c>usmHMACSHAAuthProtocol</c> is used.</p>
      </item>
      <item>
        <p><c>PrivKey</c> is a list (of integer).  This is the User's secret
          localized encryption key.  It is not visible in the MIB.  The length
          of this key needs to be 16 if <c>usmDESPrivProtocol</c> or 
          <c>usmAesCfb128Protocol</c> is used.
          </p>
      </item>
    </list>
  </section>

  <section>
    <marker id="notify"></marker>
    <title>Notify Definitions</title>
    <p>The information about Notify Definitions should be stored in a
      file called
      <c>notify.conf</c>.
      </p>
    <p>The corresponding table is <c>snmpNotifyTable</c> in the
      SNMP-NOTIFICATION-MIB.
      </p>
    <p>Each entry is a term:
      </p>
    <p><c>{NotifyName, Tag, Type}.</c></p>
    <list type="bulleted">
      <item>
        <p><c>NotifyName</c> is a unique non-empty string.
          </p>
      </item>
      <item>
        <p><c>Tag</c> is a string.
          </p>
      </item>
      <item>
        <p><c>Type</c> is <c>trap</c> or <c>inform</c>.
          </p>
      </item>
    </list>
  </section>

  <section>
    <marker id="target_addr"></marker>
    <title>Target Address Definitions</title>
    <p>The information about Target Address Definitions should be 
      stored in a file called
      <c>target_addr.conf</c>.
      </p>
    <p>The corresponding tables are <c>snmpTargetAddrTable</c> in the
      SNMP-TARGET-MIB and <c>snmpTargetAddrExtTable</c> in the SNMP-COMMUNITY-MIB.
      </p>
    <p>Each entry is a term:
      </p>
    <p><c>{TargetName, Ip, Udp, Timeout, RetryCount, TagList, ParamsName, EngineId}.</c> or      <br></br>
<c>{TargetName, Ip, Udp, Timeout, RetryCount, TagList, ParamsName, EngineId, TMask, MaxMessageSize}.</c></p>
    <list type="bulleted">
      <item>
        <p><c>TargetName</c> is a unique non-empty string.
          </p>
      </item>
      <item>
        <p><c>Ip</c> is a list of four integers.     
          </p>
      </item>
      <item>
        <p><c>Udp</c> is an integer.
          </p>
      </item>
      <item>
        <p><c>Timeout</c> is an integer.
          </p>
      </item>
      <item>
        <p><c>RetryCount</c> is an integer.
          </p>
      </item>
      <item>
        <p><c>TagList</c> is a string.
          </p>
      </item>
      <item>
        <p><c>ParamsName</c> is a string.
          </p>
      </item>
      <item>
        <p><c>EngineId</c> is a string or the atom <c>discovery</c>.
          </p>
      </item>
      <item>
        <p><c>TMask</c> is a string of size 0, or size 6 (default: []).
          </p>
      </item>
      <item>
        <p><c>MaxMessageSize</c> is an integer (default: 2048).
          </p>
      </item>
    </list>
    <p>Note that if <c>EngineId</c> has the value <c>discovery</c>, 
      the agent cannot send
      <c>inform</c> messages to that manager until it has performed the
      <em>discovery</em> process with that manager. </p>
  </section>

  <section>
    <marker id="target_params"></marker>
    <title>Target Parameters Definitions</title>
    <p>The information about Target Parameters Definitions should be
      stored in a file called
      <c>target_params.conf</c>.
      </p>
    <p>The corresponding table is <c>snmpTargetParamsTable</c> in the
      SNMP-TARGET-MIB.
      </p>
    <p>Each entry is a term:
      </p>
    <p><c>{ParamsName, MPModel, SecurityModel, SecurityName, SecurityLevel}.</c></p>
    <list type="bulleted">
      <item>
        <p><c>ParamsName</c> is a unique non-empty string.
          </p>
      </item>
      <item>
        <p><c>MPModel</c> is <c>v1</c>, <c>v2c</c> or <c>v3</c></p>
      </item>
      <item>
        <p><c>SecurityModel</c> is <c>v1</c>, <c>v2c</c>, or <c>usm</c>.
          </p>
      </item>
      <item>
        <p><c>SecurityName</c> is a string.
          </p>
      </item>
      <item>
        <p><c>SecurityLevel</c> is <c>noAuthNoPriv</c>, <c>authNoPriv</c>
          or <c>authPriv</c>.
          </p>
      </item>
    </list>
  </section>
</chapter>

