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<!DOCTYPE chapter SYSTEM "chapter.dtd">

<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>Running the application</title>
    <prepared></prepared>
    <responsible></responsible>
    <docno></docno>
    <approved></approved>
    <checked></checked>
    <date></date>
    <rev></rev>
    <file>snmp_config.xml</file>
  </header>
  <p>The chapter <em>Running the application</em> describes how the 
    application is configured and started.
    The topics include:</p>
  <list type="bulleted">
    <item>configuration directories and parameters</item>
    <item>modifying the configuration files</item>
    <item>starting the application (agent and/or manager)</item>
    <item>debugging the application (agent and/or manager)</item>
  </list>
  <p>Refer also to the chapter(s) 
    <seealso marker="snmp_agent_config_files">Definition of Agent  Configuration Files</seealso> and  
    <seealso marker="snmp_manager_config_files">Definition of Manager  Configuration Files</seealso> which contains more detailed information 
    about the agent and manager configuration files.</p>

  <section>
    <marker id="configuration_params"></marker>
    <title>Configuring the application</title>
    <p>The following two directories must exist in the system
      to run the agent:</p>
    <list type="bulleted">
      <item>
        <p>the <em>configuration directory</em> stores all
          configuration files used by the agent (refer to the chapter 
          <seealso marker="snmp_agent_config_files">Definition of Agent Configuration Files</seealso> for more information). </p>
      </item>
      <item>the <em>database directory</em> stores the internal
       database files.</item>
    </list>
    <p>The following directory must exist in the system
      to run the manager:</p>
    <list type="bulleted">
      <item>
        <p>the <em>configuration directory</em> stores all
          configuration files used by the manager (refer to the chapter 
          <seealso marker="snmp_manager_config_files">Definition of Manager  Configuration Files</seealso> for more information). </p>
      </item>
      <item>
         <p>the <em>database directory</em> stores the internal
           database files. </p>
      </item>
    </list>

    <!-- The info below is also found in the snmp_app.xml file -->

    <p>The agent and manager uses (application) configuration parameters to 
      find out where these directories are located. The parameters should be
      defined in an Erlang system configuration file. The following
      configuration parameters are defined for the SNMP application:</p>

    <pre>
      agent_options() = [agent_option()]
      agent_option() = {restart_type,     restart_type()}     | 
                       {agent_type,       agent_type()}       |  
                       {agent_verbosity,  verbosity()}        |  
                       {versions,         versions()}         |  
                       {discovery,        agent_discovery()}  |  
                       {priority,         priority()}         |  
                       {multi_threaded,   multi_threaded()}   |  
                       {db_dir,           db_dir()}           |  
                       {db_init_error,    db_init_error()}    |  
                       {local_db,         local_db()}         |  
                       {net_if,           agent_net_if()}     |  
                       {mibs,             mibs()}             |  
                       {mib_storage,      mib_storage()}      |  
                       {mib_server,       mib_server()}       |  
                       {audit_trail_log,  audit_trail_log()}  |  
                       {error_report_mod, error_report_mod()} |  
                       {note_store,       note_store()}       |  
                       {symbolic_store,   symbolic_store()}   |  
                       {target_cache,     target_cache()}     |  
                       {config,           agent_config()}
      manager_options() = [manager_option()]
      manager_option() = {restart_type,             restart_type()}    | 
                         {net_if,                   manager_net_if()}  |  
                         {server,                   server()}          | 
                         {note_store,               note_store()}      | 
                         {config,                   manager_config()}  |  
                         {inform_request_behaviour, manager_irb()}     | 
                         {mibs,                     manager_mibs()}    | 
                         {priority,                 priority()}        |  
                         {audit_trail_log,          audit_trail_log()} | 
                         {versions,                 versions()}        | 
                         {def_user_mod,             def_user_module()  | 
                         {def_user_data,            def_user_data()}
    </pre>

    <p>Agent specific config options and types:</p>
    <taglist>
      <tag><c><![CDATA[agent_type() = master | sub <optional>]]></c></tag>
      <item>
        <p>If <c>master</c>, one master agent is
          started. Otherwise, no agents are started. </p>
        <p>Default is <c>master</c>.</p>
      </item>

      <tag><c><![CDATA[agent_discovery() = [agent_discovery_opt()] <optional>]]></c></tag>
      <item>
        <p><c>agent_discovery_opt() = 
          {terminating, agent_terminating_discovery_opts()} | 
          {originating, agent_originating_discovery_opts()}</c></p>
        <p>The <c>terminating</c> options effects discovery initiated by 
          a manager. </p>
        <p>The <c>originating</c> options effects discovery initiated 
          by this agent. </p>
        <p>For defaults see the options in <c>agent_discovery_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[agent_terminating_discovery_opts() = [agent_terminating_discovery_opt()] <optional>]]></c></tag>
      <item>
        <p><c>agent_terminating_discovery_opt() = 
          {enable, boolean()} | 
          {stage2, discovery | plain} | 
          {trigger_username, string()}</c></p>
        <p>These are options effecting discovery <c>terminating</c> in this
          agent (i.e. initiated by a manager). </p>
        <p>The default values for the <c>terminating</c> 
          discovery options are: </p>
        <list type="bulleted">
          <item>enable: <c>true</c></item>
          <item>stage2: <c>discovery</c></item>
          <item>trigger_username: <c>""</c></item>
        </list>
      </item>

      <tag><c><![CDATA[agent_originating_discovery_opts() = [agent_originating_discovery_opt()] <optional>]]></c></tag>
      <item>
        <p><c>agent_originating_discovery_opt() = 
          {enable, boolean()}</c></p>
        <p>These are options effecting discovery <c>originating</c> in this
          agent. </p>
        <p>The default values for the <c>originating</c> 
          discovery options are: </p>
        <list type="bulleted">
          <item>enable: <c>true</c></item>
        </list>
      </item>

      <tag><c><![CDATA[multi_threaded() = bool() <optional>]]></c></tag>
      <item>
        <p>If <c>true</c>, the agent is multi-threaded, with one
          thread for each get request. </p>
        <p>Default is <c>false</c>.</p>
      </item>

      <tag><c><![CDATA[db_dir() = string() <mandatory>]]></c></tag>
      <item>
        <p>Defines where the SNMP agent internal db files are stored.</p>
      </item>

      <tag><c><![CDATA[local_db() = [local_db_opt()] <optional>]]></c></tag>
      <item>
        <p><c>local_db_opt() = {repair, agent_repair()} | {auto_save, agent_auto_save()} |   {verbosity, verbosity()}</c></p>
        <p>Defines options specific for the SNMP agent local database.</p>
        <p>For defaults see the options in <c>local_db_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[agent_repair() = false | true | force <optional>]]></c></tag>
      <item>
        <p>When starting snmpa_local_db it always tries to open an
          existing database. If <c>false</c>, and some errors occur, a new
          database is created instead. If <c>true</c>, an existing file
          will be repaired. If <c>force</c>, the table will be repaired
          even if it was properly closed. </p>
        <p>Default is <c>true</c>.</p>
      </item>

      <tag><c><![CDATA[agent_auto_save() = integer() | infinity <optional>]]></c></tag>
      <item>
        <p>The auto save interval. The table is flushed to disk
          whenever not accessed for this amount of time.</p>
        <p>Default is <c>5000</c>.</p>
      </item>

      <tag><c><![CDATA[agent_net_if() = [agent_net_if_opt()] <optional>]]></c></tag>
      <item>
        <p><c>agent_net_if_option() = {module, agent_net_if_module()} | 
            {verbosity, verbosity()} | 
            {options, agent_net_if_options()}</c></p>
        <p>Defines options specific for the SNMP agent network interface 
          entity. </p>
        <p>For defaults see the options in <c>agent_net_if_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[agent_net_if_module() = atom() <optional>]]></c></tag>
      <item>
        <p>Module which handles the network interface part for the
          SNMP agent. Must implement the 
          <seealso marker="snmpa_network_interface">snmpa_network_interface</seealso> behaviour.</p>
        <p>Default is <c>snmpa_net_if</c>.</p>
      </item>

      <tag><c><![CDATA[agent_net_if_options() = [agent_net_if_option()] <optional>]]></c></tag>
      <item>
        <p><c>agent_net_if_option() = {bind_to, bind_to()} |  
            {sndbuf, sndbuf()} |  
            {recbuf, recbuf()} |  
            {no_reuse, no_reuse()} | 
	    {req_limit, req_limit()} |
            {filter, agent_net_if_filter_options()}</c></p>
        <p>These options are actually specific to the used module.
          The ones shown here are applicable to the default 
          <c>agent_net_if_module()</c>.</p>
        <p>For defaults see the options in <c>agent_net_if_option()</c>.</p>
      </item>

      <tag><c><![CDATA[agent_net_if_filter_options() = [agent_net_if_filter_option()] <optional>]]></c></tag>
      <item>
	<p><c><![CDATA[agent_net_if_filter_option() = {module, agent_net_if_filter_module()}]]></c></p>
	<p>These options are actually specific to the used module.
	  The ones shown here are applicable to the default 
	  <c>agent_net_if_filter_module()</c>.</p>
	<p>For defaults see the options in <c>agent_net_if_filter_option()</c>.</p>
      </item>

      <tag><c><![CDATA[agent_net_if_filter_module() = atom() <optional>]]></c></tag>
      <item>
	<p>Module which handles the network interface filter part for the
	  SNMP agent. Must implement the 
	  <seealso marker="snmpa_network_interface_filter">snmpa_network_interface_filter
	    </seealso> behaviour.</p>
	<p>Default is <c>snmpa_net_if_filter</c>.</p>
      </item>

      <tag><c><![CDATA[req_limit() = integer() | infinity <optional>]]></c></tag>
      <item>
        <p>Max number of simultaneous requests handled by the agent.</p>
        <p>Default is <c>infinity</c>.</p>
      </item>

      <tag><c><![CDATA[agent_mibs() = [string()] <optional>]]></c></tag>
      <item>
        <p>Specifies a list of MIBs (including path) that defines which MIBs
          are initially loaded into the SNMP master agent. </p>
        <p>Note that the following will always be loaded:</p>
        <list type="bulleted">
          <item>version v1: <c>STANDARD-MIB</c></item>
          <item>version v2: <c>SNMPv2</c></item>
          <item>version v3: <c>SNMPv2</c>, <c>SNMP-FRAMEWORK-MIB</c> 
           and <c>SNMP-MPD-MIB</c></item>
        </list>
        <p>Default is <c>[]</c>.</p>
      </item>

      <tag><c><![CDATA[mib_storage() = ets | {ets, Dir} | {ets, Dir, Action} | dets | {dets, Dir} | {dets, Dir, Action} | mnesia | {mnesia, Nodes} | {mnesia, Nodes, Action} <optional>]]></c></tag>
      <item>
        <p>Specifies how info retrieved from the mibs will be stored.</p>
        <p>If <c>mib_storage</c> is <c>{ets, Dir}</c>, the table will also be 
          stored on file. If <c>Dir</c> is <c>default</c>, then <c>db_dir</c> 
          will be used.</p>
        <p>If <c>mib_storage</c> is <c>dets</c> or if <c>Dir</c> is 
          <c>default</c>, then <c>db_dir</c> will be used for <c>Dir</c>.</p>
        <p>If <c>mib_storage</c> is <c>mnesia</c> then <c>erlang:nodes()</c>
          will be used for <c>Nodes</c>.</p>
        <p>Default is <c>ets</c>. </p>
        <p><c>Dir = default | string()</c>. Dir is the directory where the 
          files will be stored. If <c>default</c>, then <c>db_dir</c> will be 
          used.</p>
        <p><c>Nodes = visible | connected | [node()]</c>. 
          <c>Nodes = visible</c> is translated to 
          <c>erlang:nodes(visible)</c>. 
          <c>Nodes = connected</c> is translated to 
          <c>erlang:nodes(connected)</c>. 
          If <c>Nodes = []</c> then the own node is assumed.</p>
        <p><c>Action = clear | keep</c>. Default is <c>keep</c>.
          <c>Action</c> is used to specify what shall be done if the 
          mnesia/dets table already exist.</p>
      </item>

      <tag><c><![CDATA[mib_server() = [mib_server_opt()] <optional>]]></c></tag>
      <item>
        <p><c>mib_server_opt() = {mibentry_override, mibentry_override()} |  {trapentry_override, trapentry_override()} |  {verbosity, verbosity()} | {cache, mibs_cache()}</c></p>
        <p>Defines options specific for the SNMP agent mib server. </p>
        <p>For defaults see the options in <c>mib_server_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[mibentry_override() = bool() <optional>]]></c></tag>
      <item>
        <p>If this value is false, then when loading a mib each mib-
          entry is checked prior to installation of the mib. 
          The purpose of the check is to prevent that the same symbolic 
          mibentry name is used for different oid's.</p>
        <p>Default is <c>false</c>.</p>
      </item>

      <tag><c><![CDATA[trapentry_override() = bool() <optional>]]></c></tag>
      <item>
        <p>If this value is false, then when loading a mib each trap
          is checked prior to installation of the mib. 
          The purpose of the check is to prevent that the same symbolic 
          trap name is used for different trap's.</p>
        <p>Default is <c>false</c>.</p>
      </item>

      <tag><c><![CDATA[mibs_cache() = bool() | mibs_cache_opts() <optional>]]></c></tag>
      <item>
        <p>Shall the agent utilize the mib server lookup cache or not.</p>
        <p>Default is <c>true</c> (in which case the <c>mibs_cache_opts()</c> 
          default values apply).</p>
      </item>

      <tag><c><![CDATA[mibs_cache_opts() = [mibs_cache_opt()] <optional>]]></c></tag>
      <item>
        <p><c>mibs_cache_opt() = {autogc, mibs_cache_autogc()} | {gclimit, mibs_cache_gclimit()} | {age, mibs_cache_age()}</c></p>
        <p>Defines options specific for the SNMP agent mib server cache. </p>
        <p>For defaults see the options in <c>mibs_cache_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[mibs_cache_autogc() = bool() <optional>]]></c></tag>
      <item>
        <p>Defines if the mib server shall perform cache gc automatically or 
          leave it to the user (see 
          <seealso marker="snmpa#gc_mibs_cache">gc_mibs_cache/0,1,2,3</seealso>). </p>
        <p>Default is <c>true</c>.</p>
      </item>

      <tag><c><![CDATA[mibs_cache_age() = integer() > 0 <optional>]]></c></tag>
      <item>
        <p>Defines how old the entries in the cache will be allowed before 
          they are GC'ed (assuming GC is performed). Each entry in the 
          cache is "touched" whenever it is accessed. </p>
        <p>The age is defined in milliseconds. </p>
        <p>Default is <c>10 timutes</c>.</p>
      </item>

      <tag><c><![CDATA[mibs_cache_gclimit() = integer() > 0 | infinity <optional>]]></c></tag>
      <item>
        <p>When performing a GC, this is the max number of cache entries 
          that will be deleted from the cache. </p>
        <p>The reason for having this limit is that if the cache is 
          large, the GC can potentially take a long time, during which 
          the agent is locked. </p>
        <p>Default is <c>100</c>.</p>
      </item>

      <tag><c><![CDATA[error_report_mod() = atom() <optional>]]></c></tag>
      <item>
        <p>Defines an error report module, implementing the 
          <seealso marker="snmpa_error_report">snmpa_error_report</seealso> 
          behaviour. Two modules are provided with the toolkit: 
          <c>snmpa_error_logger</c> and <c>snmpa_error_io</c>.</p>
        <p>Default is <c>snmpa_error_logger</c>.</p>
      </item>

      <tag><c>symbolic_store() = [symbolic_store_opt()]</c></tag>
      <item>
        <p><c>symbolic_store_opt() = {verbosity, verbosity()}</c></p>
        <p>Defines options specific for the SNMP agent symbolic store. </p>
        <p>For defaults see the options in <c>symbolic_store_opt()</c>.</p>
      </item>

      <tag><c>target_cache() = [target_cache_opt()]</c></tag>
      <item>
        <p><c>target_cache_opt() = {verbosity, verbosity()}</c></p>
        <p>Defines options specific for the SNMP agent target cache. </p>
        <p>For defaults see the options in <c>target_cache_opt()</c>.</p>
      </item>
      <tag><c><![CDATA[agent_config() = [agent_config_opt()] <mandatory>]]></c></tag>
      <item>
        <p><c>agent_config_opt() = {dir, agent_config_dir()} |  {force_load, force_load()} | {verbosity, verbosity()}</c></p>
        <p>Defines specific config related options for the SNMP agent. </p>
        <p>For defaults see the options in <c>agent_config_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[agent_config_dir = dir() <mandatory>]]></c></tag>
      <item>
        <p>Defines where the SNMP agent configuration files are stored.</p>
      </item>

      <tag><c><![CDATA[force_load() = bool() <optional>]]></c></tag>
      <item>
        <p>If <c>true</c> the configuration files are re-read
          during start-up, and the contents of the configuration 
          database ignored.  Thus, if <c>true</c>, changes to 
          the configuration database are lost upon reboot of the 
          agent. </p>
        <p>Default is <c>false</c>.</p>
      </item>
    </taglist>

    <p>Manager specific config options and types:</p>
    <taglist>
      <tag><c><![CDATA[server() = [server_opt()] <optional>]]></c></tag>
      <item>
        <p><c>server_opt() = {timeout, server_timeout()} |  {verbosity, verbosity()}</c></p>
        <p>Specifies the options for the manager server process.</p>
        <p>Default is <c>silence</c>.</p>
      </item>
      <tag><c><![CDATA[server_timeout() = integer() <optional>]]></c></tag>
      <item>
        <p>Asynchroneous request cleanup time. For every requests, 
          some info is stored internally, in order to be able to 
          deliver the reply (when it arrives) to the proper destination.
          If the reply arrives, this info will be deleted. But if
          there is no reply (in time), the info has to be deleted
          after the <em>best before</em> time has been passed.
          This cleanup will be performed at regular intervals, defined 
          by the <c>server_timeout()</c> time.
          The information will have a <em>best before</em> time,
          defined by the <c>Expire</c> time given when calling the
          request function (see 
          <seealso marker="snmpm#async_get">async_get</seealso>,
          <seealso marker="snmpm#async_get_next">async_get_next</seealso> and 
          <seealso marker="snmpm#async_set">async_set</seealso>).</p>
        <p>Time in milli-seconds.</p>
        <p>Default is <c>30000</c>.</p>
      </item>

      <tag><c><![CDATA[manager_config() = [manager_config_opt()] <mandatory>]]></c></tag>
      <item>
        <p><c>manager_config_opt() = {dir, manager_config_dir()} |  {db_dir, manager_db_dir()} |  {db_init_error, db_init_error()} |  {repair, manager_repair()} |  {auto_save, manager_auto_save()} |  {verbosity, verbosity()}</c></p>
        <p>Defines specific config related options for the SNMP manager. </p>
        <p>For defaults see the options in <c>manager_config_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[manager_config_dir = dir() <mandatory>]]></c></tag>
      <item>
        <p>Defines where the SNMP manager configuration files are stored.</p>
      </item>

      <tag><c><![CDATA[manager_db_dir = dir() <mandatory>]]></c></tag>
      <item>
        <p>Defines where the SNMP manager store persistent data.</p>
      </item>

      <tag><c><![CDATA[manager_repair() = false | true | force <optional>]]></c></tag>
      <item>
        <p>Defines the repair option for the persistent database (if 
          and how the table is repaired when opened). </p>
        <p>Default is <c>true</c>.</p>
      </item>

      <tag><c><![CDATA[manager_auto_save() = integer() | infinity <optional>]]></c></tag>
      <item>
        <p>The auto save interval. The table is flushed to disk
          whenever not accessed for this amount of time.</p>
        <p>Default is <c>5000</c>.</p>
      </item>

      <tag><c><![CDATA[manager_irb() = auto | user | {user, integer()} <optional>]]></c></tag>
      <item>
        <p>This option defines how the manager will handle the sending of 
          response (acknowledgment) to received inform-requests. </p>
        <list type="bulleted">
          <item>
            <p><c>auto</c> - The manager will autonomously send response
              (acknowledgment&gt; to inform-request messages.</p>
          </item>
          <item>
            <p><c>{user, integer()}</c> - The manager will send response
              (acknowledgment) to inform-request messages when the 
              <seealso marker="snmpm_user#handle_inform">handle_inform</seealso> 
              function completes. The integer is the time, in milli-seconds, 
              that the manager will consider the stored inform-request info 
              valid.</p>
          </item>
          <item>
            <p><c>user</c> - Same as <c>{user, integer()}</c>, except that 
              the default time, 15000 milli-seconds, is used.</p>
          </item>
        </list>
        <p>See 
          <seealso marker="snmpm_network_interface">snmpm_network_interface</seealso>, 
          <seealso marker="snmpm_user">handle_inform</seealso> and 
          <seealso marker="snmp_manager_netif">definition of the manager net if</seealso> for more info.</p>
        <p>Default is <c>auto</c>.</p>
      </item>

      <tag><c><![CDATA[manager_mibs() = [string()] <optional>]]></c></tag>
      <item>
        <p>Specifies a list of MIBs (including path) and defines which MIBs
          are initially loaded into the SNMP manager. </p>
        <p>Default is <c>[]</c>.</p>
      </item>

      <tag><c><![CDATA[manager_net_if() = [manager_net_if_opt()] <optional>]]></c></tag>
      <item>
        <p><c>manager_net_if_opt() = {module, manager_net_if_module()} | 
          {verbosity, verbosity()} | 
          {options, manager_net_if_options()}</c></p>
        <p>Defines options specific for the SNMP manager network interface 
          entity. </p>
        <p>For defaults see the options in <c>manager_net_if_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[manager_net_if_options() = [manager_net_if_option()] <optional>]]></c></tag>
      <item>
        <p><c>manager_net_if_option() = {bind_to, bind_to()} | 
          {sndbuf, sndbuf()} | 
          {recbuf, recbuf()} | 
          {no_reuse, no_reuse()} |
          {filter, manager_net_if_filter_options()}</c></p>
        <p>These options are actually specific to the used module.
          The ones shown here are applicable to the default 
          <c>manager_net_if_module()</c>.</p>
        <p>For defaults see the options in <c>manager_net_if_option()</c>.</p>
      </item>

      <tag><c><![CDATA[manager_net_if_module() = atom() <optional>]]></c></tag>
      <item>
        <p>Module which handles the network interface part for the
          SNMP manager. Must implement the 
          <seealso marker="snmpm_network_interface">snmpm_network_interface</seealso> behaviour.</p>
        <p>Default is <c>snmpm_net_if</c>.</p>
      </item>

      <tag><c><![CDATA[manager_net_if_filter_options() = [manager_net_if_filter_option()] <optional>]]></c></tag>
      <item>
	<p><c>manager_net_if_filter_option() = {module, manager_net_if_filter_module()}</c></p>
	<p>These options are actually specific to the used module.
	  The ones shown here are applicable to the default 
	  <c><![CDATA[manager_net_if_filter_module()]]></c>.</p>
	<p>For defaults see the options in 
          <c>manager_net_if_filter_option()</c>.</p>
      </item>

      <tag><c><![CDATA[manager_net_if_filter_module() = atom() <optional>]]></c></tag>
      <item>
	<p>Module which handles the network interface filter part for the
	  SNMP manager. Must implement the 
	  <seealso marker="snmpm_network_interface_filter">snmpm_network_interface_filter</seealso> behaviour.</p>
	<p>Default is <c>snmpm_net_if_filter</c>.</p>
      </item>

      <tag><c><![CDATA[def_user_module() = atom() <optional>]]></c></tag>
      <item>
        <p>The module implementing the default user. See the 
          <seealso marker="snmpm_user">snmpm_user</seealso> behaviour.</p>
        <p>Default is <c>snmpm_user_default</c>.</p>
      </item>

      <tag><c><![CDATA[def_user_data() = term() <optional>]]></c></tag>
      <item>
        <p>Data for the default user. Passed to the user when calling 
          the callback functions.</p>
        <p>Default is <c>undefined</c>.</p>
      </item>
    </taglist>

    <p>Common config types:</p>
    <taglist>
      <tag><c>restart_type() = permanent | transient | temporary</c></tag>
      <item>
        <p>See <seealso marker="stdlib:supervisor#child_spec">supervisor</seealso> 
          documentation for more info.</p>
        <p>Default is <c>permanent</c> for the agent and <c>transient</c>
          for the manager.</p>
      </item>

      <tag><c>db_init_error() = terminate | create</c></tag>
      <item>
        <p>Defines what to do if the agent is unable to open an
          existing database file. <c>terminate</c> means that the
          agent/manager will terminate and <c>create</c> means that the 
          agent/manager will remove the faulty file(s) and create new ones.</p>
        <p>Default is <c>terminate</c>.</p>
      </item>

      <tag><c><![CDATA[priority() = atom() <optional>]]></c></tag>
      <item>
        <p>Defines the Erlang priority for all SNMP processes.</p>
        <p>Default is <c>normal</c>.</p>
      </item>

      <tag><c><![CDATA[versions() = [version()] <optional>]]></c></tag>
      <item>
        <p><c>version() = v1 | v2 | v3</c></p>
        <p>Which SNMP versions shall be accepted/used.</p>
        <p>Default is <c>[v1,v2,v3]</c>.</p>
      </item>

      <tag><c><![CDATA[verbosity() = silence | info | log | debug | trace <optional>]]></c></tag>
      <item>
        <p>Verbosity for a SNMP process. This specifies now much debug info
          is printed.</p>
        <p>Default is <c>silence</c>.</p>
      </item>

      <tag><c><![CDATA[bind_to() = bool() <optional>]]></c></tag>
      <item>
        <p>If <c>true</c>, net_if binds to the IP address.
          If <c>false</c>, net_if listens on any IP address on the host
          where it is running. </p>
        <p>Default is <c>false</c>.</p>
      </item>

      <tag><c><![CDATA[no_reuse() = bool() <optional>]]></c></tag>
      <item>
        <p>If <c>true</c>, net_if does not specify that the IP
          and port address should be reusable. If <c>false</c>, 
          the address is set to reusable. </p>
        <p>Default is <c>false</c>.</p>
      </item>

      <tag><c><![CDATA[recbuf() = integer() <optional>]]></c></tag>
      <item>
        <p>Receive buffer size. </p>
        <p>Default value is defined by <c>gen_udp</c>.</p>
      </item>
      <tag><c><![CDATA[sndbuf() = integer() <optional>]]></c></tag>
      <item>
        <p>Send buffer size. </p>
        <p>Default value is defined by <c>gen_udp</c>.</p>
      </item>

      <tag><c><![CDATA[note_store() = [note_store_opt()] <optional>]]></c></tag>
      <item>
        <p><c>note_store_opt() = {timeout, note_store_timeout()} |  {verbosity, verbosity()}</c></p>
        <p>Specifies the options for the SNMP note store.</p>
        <p>For defaults see the options in <c>note_store_opt()</c>.</p>
      </item>

      <tag><c><![CDATA[note_store_timeout() = integer() <optional>]]></c></tag>
      <item>
        <p>Note cleanup time. When storing a note in the note store,
          each note is given lifetime. Every <c>timeout</c> the note_store
          process performs a GC to remove the expired note's. Time in
          milli-seconds.</p>
        <p>Default is <c>30000</c>.</p>

      <marker id="audit_trail_log"></marker>
      </item>

      <tag><c><![CDATA[audit_trail_log() [audit_trail_log_opt()] <optional>]]></c></tag>
      <item>
        <p><c>audit_trail_log_opt() = {type, atl_type()} | {dir, atl_dir()} |  {size, atl_size()} |  {repair, atl_repair()} | {seqno, atl_seqno()}</c></p>
        <p>If present, this option specifies the options for the 
          <em>audit trail logging</em>. The <c>disk_log</c> module is used 
          to maintain a wrap log. If present, the <c>dir</c> and 
          <c>size</c> options are mandatory.</p>
        <p>If not present, audit trail logging is not used.</p>
      </item>

      <tag><c><![CDATA[atl_type() = read | write | read_write <optional>]]></c></tag>
      <item>
        <p>Specifies what type of an audit trail log should be used. 
          The effect of the type is actually different for the the agent
          and the manager. </p>
        <p>For the agent:</p>
        <list type="bulleted">
          <item>If <c>write</c> is specified, only set requests are logged.  </item>
          <item>If <c>read</c> is specified, only get requests are logged.  </item>
          <item>If <c>read_write</c>, all requests are logged.  </item>
        </list>
        <p>For the manager:</p>
        <list type="bulleted">
          <item>If <c>write</c> is specified, only sent messages are logged.  </item>
          <item>If <c>read</c> is specified, only received messages are logged.  </item>
          <item>If <c>read_write</c>, both outgoing and incoming messages are 
           logged.  </item>
        </list>
        <p>Default is <c>read_write</c>.</p>
      </item>

      <tag><c><![CDATA[atl_dir = dir() <mandatory>]]></c></tag>
      <item>
        <p>Specifies where the audit trail log should be stored.</p>
        <p>If <c>audit_trail_log</c> specifies that logging should take
          place, this parameter <em>must</em> be defined.</p>
      </item>

      <tag><c><![CDATA[atl_size() = {integer(), integer()} <mandatory>]]></c></tag>
      <item>
        <p>Specifies the size of the audit
          trail log.  This parameter is sent to <c>disk_log</c>.  </p>
        <p>If <c>audit_trail_log</c> specifies that logging should 
          take place, this parameter <em>must</em> be defined.</p>
      </item>

      <tag><c><![CDATA[atl_repair() = true | false | truncate | snmp_repair <optional>]]></c></tag>
      <item>
        <p>Specifies if and how the audit trail log shall be repaired
          when opened. Unless this parameter has the value <c>snmp_repair</c>
          it is sent to <c>disk_log</c>. If, on the other hand, the value is
          <c>snmp_repair</c>, snmp attempts to handle certain faults on its
          own. And even if it cannot repair the file, it does not truncate it 
          directly, but instead <em>moves it aside</em> for later off-line 
          analysis.</p>
        <p>Default is <c>true</c>.</p>
      </item>
      <tag><c><![CDATA[atl_seqno() = true | false <optional>]]></c></tag>
      <item>
        <p>Specifies if the audit trail log entries will be (sequence)
          numbered or not. The range of the sequence numbers are according
          to RFC 5424, i.e. 1 through 2147483647. </p>
        <p>Default is <c>false</c>.</p>
      </item>
    </taglist>
  </section>

  <section>
    <title>Modifying the Configuration Files</title>
    <p>To to start the application (agent and/or manager), the 
      configuration files must be modified and there are two ways 
      of doing this. Either edit the files manually, or run the 
      configuration tool as follows.</p>
    <p>If authentication or encryption is used (SNMPv3 only), start
      the <c>crypto</c> application.</p>
    <pre>
1> snmp:config().

Simple SNMP configuration tool (version 4.0)
------------------------------------------------
Note: Non-trivial configurations still has to be
      done manually. IP addresses may be entered 
      as dront.ericsson.se (UNIX only) or
      123.12.13.23
------------------------------------------------

Configure an agent (y/n)? [y] 

Agent system config: 
--------------------
1. Agent process priority (low/normal/high) [normal] 
2. What SNMP version(s) should be used (1,2,3,1&amp;2,1&amp;2&amp;3,2&amp;3)? [3] 1&amp;2&amp;3
3. Configuration directory (absolute path)? [/ldisk/snmp] /ldisk/snmp/agent/conf
4. Config verbosity (silence/info/log/debug/trace)? [silence] 
5. Database directory (absolute path)? [/ldisk/snmp] /ldisk/snmp/agent/db
6. Mib storage type (ets/dets/mnesia)? [ets] 
7. Target cache verbosity (silence/info/log/debug/trace)? [silence] 
8. Symbolic store verbosity (silence/info/log/debug/trace)? [silence] 
9. Local DB verbosity (silence/info/log/debug/trace)? [silence] 
10. Local DB repair (true/false/force)? [true] 
11. Local DB auto save (infinity/milli seconds)? [5000] 
12. Error report module? [snmpa_error_logger] 
13. Agent type (master/sub)? [master] 
14. Master-agent verbosity (silence/info/log/debug/trace)? [silence] log
15. Shall the agent re-read the configuration files during startup 
    (and ignore the configuration database) (true/false)? [true] 
16. Multi threaded agent (true/false)? [false] true
17. Check for duplicate mib entries when installing a mib (true/false)? [false] 
18. Check for duplicate trap names when installing a mib (true/false)? [false] 
19. Mib server verbosity (silence/info/log/debug/trace)? [silence] 
20. Mib server cache (true/false)? [true]
21. Note store verbosity (silence/info/log/debug/trace)? [silence] 
22. Note store GC timeout? [30000] 
23. Shall the agent use an audit trail log (y/n)? [n] y
23b. Audit trail log type (write/read_write)? [read_write] 
23c. Where to store the audit trail log? [/ldisk/snmp] /ldisk/snmp/agent/log
23d. Max number of files? [10] 
23e. Max size (in bytes) of each file? [10240] 
23f. Audit trail log repair (true/false/truncate)? [true] 
24. Which network interface module shall be used? [snmpa_net_if] 
25. Network interface verbosity (silence/info/log/debug/trace)? [silence] log
25a. Bind the agent IP address (true/false)? [false] 
25b. Shall the agents IP address and port be not reusable (true/false)? [false] 
25c. Agent request limit (used for flow control) (infinity/pos integer)? [infinity] 32
25d. Receive buffer size of the agent (in bytes) (default/pos integer)? [default] 
25e. Send buffer size of the agent (in bytes) (default/pos integer)? [default]
25f. Do you wish to specify a network interface filter module (or use default) [default] 

Agent snmp config: 
------------------
1. System name (sysName standard variable) [bmk's agent] 
2. Engine ID (snmpEngineID standard variable) [bmk's engine] 
3. Max message size? [484] 
4. The UDP port the agent listens to. (standard 161) [4000] 
5. IP address for the agent (only used as id 
   when sending traps) [127.0.0.1] 
6. IP address for the manager (only this manager 
   will have access to the agent, traps are sent 
   to this one) [127.0.0.1] 
7. To what UDP port at the manager should traps 
   be sent (standard 162)? [5000] 
8. Do you want a none- minimum- or semi-secure configuration? 
   Note that if you chose v1 or v2, you won't get any security for these
   requests (none, minimum, semi_des, semi_aes) [minimum] 
making sure crypto server is started...
8b. Give a password of at least length 8. It is used to generate 
    private keys for the configuration:  kalle-anka
9. Current configuration files will now be overwritten. Ok (y/n)? [y] 

- - - - - - - - - - - - -
Info: 1. SecurityName "initial" has noAuthNoPriv read access
         and authenticated write access to the "restricted"
         subtree.
      2. SecurityName "all-rights" has noAuthNoPriv read/write
         access to the "internet" subtree.
      3. Standard traps are sent to the manager.
      4. Community "public" is mapped to security name "initial".
      5. Community "all-rights" is mapped to security name "all-rights".
The following agent files were written: agent.conf, community.conf,
standard.conf, target_addr.conf, target_params.conf, 
notify.conf, vacm.conf and usm.conf
- - - - - - - - - - - - -

Configure a manager (y/n)? [y] 

Manager system config: 
----------------------
1. Manager process priority (low/normal/high) [normal] 
2. What SNMP version(s) should be used (1,2,3,1&amp;2,1&amp;2&amp;3,2&amp;3)? [3] 1&amp;2&amp;3
3. Configuration directory (absolute path)? [/ldisk/snmp] /ldisk/snmp/manager/conf
4. Config verbosity (silence/info/log/debug/trace)? [silence] log
5. Database directory (absolute path)? [/ldisk/snmp] /ldisk/snmp/manager/db
6. Database repair (true/false/force)? [true] 
7. Database auto save (infinity/milli seconds)? [5000] 
8. Inform request behaviour (auto/user)? [auto] 
9. Server verbosity (silence/info/log/debug/trace)? [silence] log
10. Server GC timeout? [30000] 
11. Note store verbosity (silence/info/log/debug/trace)? [silence] 
12. Note store GC timeout? [30000] 
13. Which network interface module shall be used? [snmpm_net_if] 
14. Network interface verbosity (silence/info/log/debug/trace)? [silence] log
15. Bind the manager IP address (true/false)? [false] 
16. Shall the manager IP address and port be not reusable (true/false)? [false] 
17. Receive buffer size of the manager (in bytes) (default/pos integer)? [default] 
18. Send buffer size of the manager (in bytes) (default/pos integer)? [default] 
19. Shall the manager use an audit trail log (y/n)? [n] y
19b. Where to store the audit trail log? [/ldisk/snmp] /ldisk/snmp/manager/log
19c. Max number of files? [10] 
19d. Max size (in bytes) of each file? [10240] 
19e. Audit trail log repair (true/false/truncate)? [true] 
20. Do you wish to assign a default user [yes] or use
    the default settings [no] (y/n)? [n] 

Manager snmp config: 
--------------------
1. Engine ID (snmpEngineID standard variable) [bmk's engine] 
2. Max message size? [484] 
3. IP address for the manager (only used as id 
   when sending requests) [127.0.0.1] 
4. Port number (standard 162)? [5000] 
5. Configure a user of this manager (y/n)? [y] 
5b. User id? kalle
5c. User callback module? snmpm_user_default
5d. User (callback) data? [undefined] 
5. Configure a user of this manager (y/n)? [y] n
6. Configure an agent handled by this manager (y/n)? [y] 
6b. User id? kalle
6c. Target name? [bmk's agent] 
6d. Version (1/2/3)? [1] 3
6e. Community string ? [public] 
6f. Engine ID (snmpEngineID standard variable) [bmk's engine] 
6g. IP address for the agent [127.0.0.1] 
6h. The UDP port the agent listens to. (standard 161) [4000] 
6i. Retransmission timeout (infinity/pos integer)? [infinity] 
6j. Max message size? [484] 
6k. Security model (any/v1/v2c/usm)? [any] usm
6l. Security name? ["initial"] 
6m. Security level (noAuthNoPriv/authNoPriv/authPriv)? [noAuthNoPriv] authPriv
6. Configure an agent handled by this manager (y/n)? [y] n
7. Configure an usm user handled by this manager (y/n)? [y] 
7a. Engine ID [bmk's engine] 
7b. User name? hobbes
7c. Security name? [hobbes] 
7d. Authentication protocol (no/sha/md5)? [no] sha
7e  Authentication [sha] key (length 0 or 20)? [""] [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
7d. Priv protocol (no/des/aes)? [no] des
7f  Priv [des] key (length 0 or 16)? [""] 10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25
7. Configure an usm user handled by this manager (y/n)? [y] n
8. Current configuration files will now be overwritten. Ok (y/n)? [y] 

- - - - - - - - - - - - -
The following manager files were written: manager.conf, agents.conf , users.conf and usm.conf
- - - - - - - - - - - - -

--------------------
Configuration directory for system file (absolute path)? [/ldisk/snmp] 
ok
    </pre>
  </section>

  <section>
    <title>Starting the application</title>
    <p>Start Erlang with the command:</p>
    <code type="none">
erl -config /tmp/snmp/sys
    </code>
    <p>If authentication or encryption is used (SNMPv3 only), start
      the <c>crypto</c> application.  If this step is forgotten, the
      agent will not start, but report a
      <c>{config_error,{unsupported_crypto,_}}</c> error.</p>
    <pre>
1> <input>application:start(crypto).</input>
ok
    </pre>
    <pre>
2> <input>application:start(snmp).</input>
ok
    </pre>
  </section>

  <section>
    <marker id="verbosity"></marker>
    <title>Debugging the application</title>
    <p>It is possible to debug every (non-supervisor) process of the 
      application (both agent and manager), possibly with the exception 
      of the net_if module(s), which could be supplied by a user of the 
      application). This is done by calling the 
      <c>snmpa:verbosity/2</c> and <c>snmpm:verbosity/2</c> function(s) 
      and/or using 
      <seealso marker="#configuration_params">configuration parameters</seealso>.
      The verbosity itself has several <em>levels</em>: <c>silence | info |  log | debug | trace</c>. For the lowest verbosity <c>silence</c>, 
      nothing is printed. The higher the verbosity, the more is printed.
      Default value is always <c>silence</c>.</p>
    <pre>
3> <input>snmpa:verbosity(master_agent, log).</input>
ok
5> <input>snmpa:verbosity(net_if, log).</input>
ok
6> 
%% Example of output from the agent when a get-next-request arrives:
** SNMP NET-IF LOG: 
   got packet from {147,12,12,12}:5000

** SNMP NET-IF MPD LOG: 
   v1, community: all-rights

** SNMP NET-IF LOG: 
   got pdu from {147,12,12,12}:5000 {pdu, 'get-next-request',
                                          62612569,noError,0,
                                          [{varbind,[1,1],'NULL','NULL',1}]}

** SNMP MASTER-AGENT LOG: 
   apply: snmp_generic,variable_func,[get,{sysDescr,persistent}]

** SNMP MASTER-AGENT LOG: 
   returned: {value,"Erlang SNMP agent"}

** SNMP NET-IF LOG: 
   reply pdu: {pdu,'get-response',62612569,noError,0,
                   [{varbind,[1,3,6,1,2,1,1,1,0],
                             'OCTET STRING',
                             "Erlang SNMP agent",1}]}

** SNMP NET-IF INFO: time in agent: 19711 mysec
    </pre>

    <p>Other useful function(s) for debugging the agent are: </p>
    <taglist>
      <tag><c><![CDATA[snmpa:info/0,1]]></c></tag>
      <item>
        <p><seealso marker="snmpa#info">info</seealso> is used to retrieve a list of miscellaneous agent information.</p>
      </item>

      <tag><c><![CDATA[snmpa:which_aliasnames/0]]></c></tag>
      <item>
        <p><seealso marker="snmpa#which_aliasnames">which_aliasnames</seealso> is used to retrieve a list of all alias-names known to the agent. </p>
      </item>

      <tag><c><![CDATA[snmpa:which_tables/0]]></c></tag>
      <item>
        <p><seealso marker="snmpa#which_tables">which_tables</seealso> is used to retrieve a list of all (MIB) tables known to the agent. </p>
      </item>

      <tag><c><![CDATA[snmpa:which_variables/0]]></c></tag>
      <item>
        <p><seealso marker="snmpa#which_variables">which_variables</seealso> is used to retrieve a list of all (MIB) variables known to the agent. </p>
      </item>

      <tag><c><![CDATA[snmpa:which_notifications/0]]></c></tag>
      <item>
        <p><seealso marker="snmpa#which_notifications">which_notifications</seealso> is used to retrieve a list of all (MIB) notifications/traps known to the agent. </p>
      </item>

      <tag><c><![CDATA[snmpa:restart_worker/0,1]]></c></tag>
      <item>
        <p><seealso marker="snmpa#restart_worker">restart_worker</seealso> is used to restart the worker process of a multi-threaded agent. </p>
      </item>

      <tag><c><![CDATA[snmpa:restart_set_worker/0,1]]></c></tag>
      <item>
        <p><seealso marker="snmpa#restart_set_worker">restart_set_worker</seealso> is used to restart the set-worker process of a multi-threaded agent. </p>
      </item>

      <tag><c><![CDATA[snmpa_local_db:print/0,1,2]]></c></tag>
      <item>
        <p>For example, this function can show the counters 
          <c>snmpInPkts</c> and <c>snmpOutPkts</c>.</p>
      </item>
    </taglist>

    <p>Another usefull way to debug the agent is to pretty-print the content of 
    all the tables and/or variables handled directly by the agent. 
    This can be done by simply calling: </p>
    <p><c><![CDATA[snmpa:print_mib_info()]]></c></p>
    <p>See 
    <seealso marker="snmpa#print_mib_info">print_mib_info/0</seealso>, 
    <seealso marker="snmpa#print_mib_tables">print_mib_tables/0</seealso>
    or
    <seealso marker="snmpa#print_mib_variables">print_mib_variables/0</seealso> 
    for more info. </p>
      
  </section>
</chapter>

