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<chapter>
  <header>
    <copyright>
      <year>1997</year><year>2016</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
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    <legalnotice>
      Licensed under the Apache License, Version 2.0 (the "License");
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      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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    <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 
  <seeguide marker="snmp_agent_funct_descr#management">Management of the Agent</seeguide> 
  for a description of the MIBs). </p>
  <p>The files are: </p>
  <list type="bulleted">
    <item>
      <p><c>agent.conf</c>: see 
        <seeguide marker="#agent_information">Agent Information</seeguide></p>
    </item>
    <item>
      <p><c>standard.conf</c>: see 
        <seeguide marker="#system_information">System Information</seeguide></p>
    </item>
    <item>
      <p><c>context.conf</c>: see 
        <seeguide marker="#context">Contexts</seeguide></p>
    </item>
    <item>
      <p><c>community.conf</c>: see 
        <seeguide marker="#community">Communities</seeguide></p>
    </item>
    <item>
      <p><c>target_addr.conf</c>: see 
        <seeguide marker="#target_addr">Target Address Definitions</seeguide></p>
    </item>
    <item>
      <p><c>target_params.conf</c>: see 
        <seeguide marker="#target_params">Target Parameters Definitions</seeguide></p>
    </item>
    <item>
      <p><c>vacm.conf</c>: see 
        <seeguide marker="#vacm">MIB Views for VACM</seeguide></p>
    </item>
    <item>
      <p><c>usm.conf</c>: see 
        <seeguide marker="#usm">Security data for USM</seeguide></p>
    </item>
    <item>
      <p><c>notify.conf</c>: see 
        <seeguide marker="#notify">Notify Definitions</seeguide></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>
  
  <marker id="agent_information"></marker>
  
  <section>
    <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>
	<p><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>intAgentTransports</c>, which defines the
	transport domains and addresses of the agent. </p>
      </item>
      <item>
	<p><c>Value</c> is the value for the variable.</p>
      </item>
    </list>
    <p>The following example shows an <c>agent.conf</c> file: </p>
    <pre>
{intAgentUDPPort, 4000}.
{intAgentTransports,
 [{transportDomainUdpIpv4, {141,213,11,24}},
  {transportDomainUdpIpv6, {0,0,0,0,0,0,0,1}}]}.
{snmpEngineID, "mbj's engine"}.
{snmpEngineMaxPacketSize, 484}.
    </pre>
    <p>The value of <c>intAgentTransports</c> is a list of
    <c>{Domain, Addr}</c> tuples, where <c>Domain</c>
    is either <c>transportDomainUdpIpv4</c> or <c>transportDomainUdpIpv6</c>,
    and <c>Addr</c> is the address in the domain.
    <c>Addr</c> can be specified either as an
    <c>IpAddr</c> or as an <c>{IpAddr, IpPort}</c> tuple.
    <c>IpAddr</c> is either a regular Erlang/OTP
    <seetype marker="kernel:inet#ip_address"><c>ip_address()</c></seetype>
    or a traditional SNMP integer list and <c>IpPort</c> is an integer.
    </p>

    <p>When the <c>Addr</c> value does not contain a port number,
    the value of <c>intAgentUDPPort</c> is used.</p>

    <p>The legacy and intermediate variables <c>intAgentIpAddress</c>
    and <c>intAgentTransportDomain</c> are still supported so old
    <c>agent.conf</c> files will work.
    </p>

    <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>

    <marker id="context"></marker>
  </section>

  <section>
    <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>
	<p><c>ContextName</c> is a string.</p>
      </item>
    </list>

    <marker id="system_information"></marker>
  </section>

  <section>
    <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>
	<p><c>SystemVariable</c> is one of the variables in the
	system group, or <c>snmpEnableAuthenTraps</c>. </p>
      </item>
      <item>
	<p><c>Value</c> is the value for the variable. </p>
      </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>

    <marker id="community"></marker>
  </section>

  <section>
    <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>
	<p><c>CommunityIndex</c> is a non-empty string.</p>
      </item>
      <item>
	<p><c>CommunityName</c> is a string.</p>
      </item>
      <item>
	<p><c>SecurityName</c> is a string.</p>
      </item>
      <item>
	<p><c>ContextName</c> is a string.</p>
      </item>
      <item>
	<p><c>TransportTag</c> is a string.</p>
      </item>
    </list>

    <marker id="vacm"></marker>
  </section>

  <section>
    <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>

    <marker id="usm"></marker>
  </section>

  <section>
    <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>

    <marker id="notify"></marker>
  </section>

  <section>
    <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>

    <marker id="target_addr"></marker>
  </section>

  <section>
    <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, Domain, Addr, Timeout, RetryCount, TagList, ParamsName, EngineId}.</c>
    <br></br> or <br></br>
    <c>{TargetName, Domain, Addr, 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>Domain</c> is one of the atoms: 
	<c>transportDomainUdpIpv4</c> | <c>transportDomainUdpIpv6</c>. </p>
      </item>
      <item>
	<p><c>Addr</c> is either an <c>IpAddr</c> or
	an <c>{IpAddr, IpPort}</c> tuple. <c>IpAddr</c> is either
	a regular Erlang/OTP
	<seetype marker="kernel:inet#ip_address"><c>ip_address()</c></seetype>
	or a traditional SNMP integer list, and <c>IpPort</c> is an integer.</p>
	<p>If <c>IpPort</c> is omitted <c>162</c> is used.</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 specified just as <c>Addr</c> or as <c>[]</c>.
	Note in particular that using a list of 6 bytes	for IPv4
	or 8 words plus 2 bytes for IPv6 are still valid address formats
	so old configurations will work.</p>
      </item>
      <item>
        <p><c>MaxMessageSize</c> is an integer (default: 2048). </p>
      </item>
    </list>
    <p>The old tuple formats with <c>Ip</c> address and <c>Udp</c>
    port number found in old configurations still work.</p>
    <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>
    
    <marker id="target_params"></marker>
  </section>

  <section>
    <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>

