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NAME

       snmp - The SNMP Application

DESCRIPTION

       This  chapter  describes  the  snmp  application in OTP. The SNMP application provides the
       following services:

         * a multilingual extensible SNMP agent

         * a SNMP manager

         * a MIB compiler

CONFIGURATION

       The following configuration parameters are defined for  the  SNMP  application.  Refer  to
       application(3erl) for more information about configuration parameters.

       The  snmp part of the config file specifying the configuration parameters is basically the
       following tuple:

             {snmp, snmp_components_config()}

       A minimal config file for starting a node with both a manager and an agent:

             [{snmp,
               [{agent, [{db_dir, "/tmp/snmp/agent/db"},
                         {config, [{dir, "/tmp/snmp/agent/conf"}]}]},
                {manager, [{config, [{dir, "/tmp/snmp/manager/conf"},
                                     {db_dir, "/tmp/snmp/manager/db"}]}]}]}
               ]
              }
             ].

       Each snmp component has its own set of configuration parameters, even though some  of  the
       types are common to both components.

             snmp_components_config() -> [snmp_component_config()]
             snmp_component_config() -> {agent, agent_options()} | {manager, manager_options()}
             agent_options() = [agent_option()]
             agent_option() = {restart_type,     restart_type()}     |
                              {agent_type,       agent_type()}       |
                              {agent_verbosity,  verbosity()}        |
                              {discovery,        agent_discovery()}  |
                              {versions,         versions()}         |
                              {gb_max_vbs,       gb_max_vbs()}       |
                              {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()}

       Agent specific config options and types:

         agent_type() = master | sub <optional>:
           If master, one master agent is started. Otherwise, no agents are started.

           Default is master.

         agent_discovery() = [agent_discovery_opt()] <optional>:
           agent_discovery_opt()    =    {terminating,    agent_terminating_discovery_opts()}   |
           {originating, agent_originating_discovery_opts()}

           The terminating options effects discovery initiated by a manager.

           The originating options effects discovery initiated by this agent.

           For defaults see the options in agent_discovery_opt().

         agent_terminating_discovery_opts() = [agent_terminating_discovery_opt()] <optional>:
           agent_terminating_discovery_opt() = {enable, boolean()} | {stage2, discovery |  plain}
           | {trigger_username, string()}

           These  are  options effecting discovery terminating in this agent (i.e. initiated by a
           manager).

           The default values for the terminating discovery options are:

           * enable: true

           * stage2: discovery

           * trigger_username: ""

         agent_originating_discovery_opts() = [agent_originating_discovery_opt()] <optional>:
           agent_originating_discovery_opt() = {enable, boolean()}

           These are options effecting discovery originating in this agent.

           The default values for the originating discovery options are:

           * enable: true

         multi_threaded() = bool() <optional>:
           If true, the agent is multi-threaded, with one thread for each get request.

           Default is false.

         db_dir() = string() <mandatory>:
           Defines where the SNMP agent internal db files are stored.

         gb_max_vbs() = pos_integer() | infinity <optional>:
           Defines the maximum number of varbinds allowed in a Get-BULK response.

           Default is 1000.

         local_db() = [local_db_opt()] <optional>:
           local_db_opt()  =  {repair,  agent_repair()}  |   {auto_save,   agent_auto_save()}   |
           {verbosity, verbosity()}

           Defines options specific for the SNMP agent local database.

           For defaults see the options in local_db_opt().

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

           Default is true.

         agent_auto_save() = integer() | infinity <optional>:
           The  auto  save  interval. The table is flushed to disk whenever not accessed for this
           amount of time.

           Default is 5000.

         agent_net_if() = [agent_net_if_opt()] <optional>:
           agent_net_if_opt() = {module,  agent_net_if_module()}  |  {verbosity,  verbosity()}  |
           {options, agent_net_if_options()}

           Defines options specific for the SNMP agent network interface entity.

           For defaults see the options in agent_net_if_opt().

         agent_net_if_module() = atom() <optional>:
           Module which handles the network interface part for the SNMP agent. Must implement the
           snmpa_network_interface behaviour.

           Default is snmpa_net_if.

         agent_net_if_options() = [agent_net_if_option()] <optional>:
           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()}

           These options are actually specific to the  used  module.  The  ones  shown  here  are
           applicable to the default agent_net_if_module().

           For defaults see the options in agent_net_if_option().

         req_limit() = integer() | infinity <optional>:
           Max number of simultaneous requests handled by the agent.

           Default is infinity.

         agent_net_if_filter_options() = [agent_net_if_filter_option()] <optional>:
           agent_net_if_filter_option() = {module, agent_net_if_filter_module()}

           These  options  are  actually  specific  to  the  used module. The ones shown here are
           applicable to the default agent_net_if_filter_module().

           For defaults see the options in agent_net_if_filter_option().

         agent_net_if_filter_module() = atom() <optional>:
           Module which handles the network interface  filter  part  for  the  SNMP  agent.  Must
           implement the snmpa_network_interface_filter behaviour.

           Default is snmpa_net_if_filter.

         agent_mibs() = [string()] <optional>:
           Specifies a list of MIBs (including path) that defines which MIBs are initially loaded
           into the SNMP master agent.

           Note that the following mibs will always be loaded:

           * version v1: STANDARD-MIB

           * version v2: SNMPv2

           * version v3: SNMPv2, SNMP-FRAMEWORK-MIB and SNMP-MPD-MIB

           Default is [].

         mib_storage() = [mib_storage_opt()] <optional>:
           mib_storage_opt() = {module, mib_storage_module()} | {options, mib_storage_options()}

           This option specifies how basic mib data is stored. This option is used by  two  parts
           of the snmp agent: The mib-server and the symbolic-store.

           Default is [{module, snmpa_mib_storage_ets}].

         mib_storage_module()  = snmpa_mib_data_ets | snmpa_mib_data_dets | snmpa_mib_data_mnesia
         | module():
           Defines the mib storage module of the SNMP agent as defined by  the  snmpa_mib_storage
           behaviour.

           Several  entities  (mib-server  via the its data module and the symbolic-store) of the
           snmp agent uses this for storage of miscelaneous  mib  related  data  retrieved  while
           loading a mib.

           There  are  several  implementations  provided  with the agent: snmpa_mib_storage_ets,
           snmpa_mib_storage_dets and snmpa_mib_storage_mnesia.

           Default module is snmpa_mib_storage_ets.

         mib_storage_options() = list() <optional>:
           This is implementattion depended. That is, it depends on the module. For each module a
           specific set of options are valid. For the module provided with the app, these options
           are supported:

           * snmpa_mib_storage_ets: {dir,  filename()}  |  {action,  keep  |  clear},  {checksum,
             boolean()}

             * dir  - If present, points to a directory where a file to which all data in the ets
               table is "synced".

               Also, when a table is opened this file is read, if it exists.

               By default, this will not be used.

             * action - Specifies the behaviour when a non-empty file is found: Keep its  content
               or clear it out.

               Default is keep.

             * checksum - Defines if the file is checksummed or not.

               Default is false.

           * snmpa_mib_storage_dets:  {dir,  filename()}  |  {action,  keep | clear}, {auto_save,
             default | pos_integer()} | {repair, force | boolean()}

             * dir - This mandatory option points to a directory where to place  the  file  of  a
               dets table.

             * action  - Specifies the behaviour when a non-empty file is found: Keep its content
               or clear it out.

               Default is keep.

             * auto_save - Defines the dets auto-save frequency.

               Default is default.

             * repair - Defines the dets repair behaviour.

               Default is false.

           * snmpa_mib_storage_mnesia: {action, keep | clear}, {nodes, [node()]}

             * action - Specifies the behaviour when a non-empty, already existing,  table:  Keep
               its content or clear it out.

               Default is keep.

             * nodes  -  A  list  of  node names (or an atom describing a list of nodes) defining
               where to open the table. Its up to the user to  ensure  that  mnesia  is  actually
               running on the specified nodes.

               The following distinct values are recognised:

               * [] - Translated into a list of the own node: [node()]

               * all - erlang:nodes()

               * visible - erlang:nodes(visible)

               * connected - erlang:nodes(connected)

               * db_nodes - mnesia:system_info(db_nodes)

               Default is the result of the call: erlang:nodes().

         mib_server() = [mib_server_opt()] <optional>:
           mib_server_opt()  =  {mibentry_override,  mibentry_override()}  | {trapentry_override,
           trapentry_override()}  |  {verbosity,   verbosity()}   |   {cache,   mibs_cache()}   |
           {data_module, mib_server_data_module()}

           Defines options specific for the SNMP agent mib server.

           For defaults see the options in mib_server_opt().

         mibentry_override() = bool() <optional>:
           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.

           Default is false.

         trapentry_override() = bool() <optional>:
           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.

           Default is false.

         mib_server_data_module() = snmpa_mib_data_tttn | module() <optional>:
           Defines  the  backend  data  module  of  the  SNMP  agent mib-server as defined by the
           snmpa_mib_data behaviour.

           At present only the default module is provided with the agent, snmpa_mib_data_tttn.

           Default module is snmpa_mib_data_tttn.

         mibs_cache() = bool() | mibs_cache_opts() <optional>:
           Shall the agent utilize the mib server lookup cache or not.

           Default is true (in which case the mibs_cache_opts() default values apply).

         mibs_cache_opts() = [mibs_cache_opt()] <optional>:
           mibs_cache_opt() = {autogc, mibs_cache_autogc()} | {gclimit,  mibs_cache_gclimit()}  |
           {age, mibs_cache_age()}

           Defines options specific for the SNMP agent mib server cache.

           For defaults see the options in mibs_cache_opt().

         mibs_cache_autogc() = bool() <optional>:
           Defines if the mib server shall perform cache gc automatically or leave it to the user
           (see gc_mibs_cache/0,1,2,3).

           Default is true.

         mibs_cache_age() = integer() > 0 <optional>:
           Defines how old the entries in the cache will be allowed to  become  before  they  are
           GC'ed  (assuming GC is performed). Each entry in the cache is "touched" whenever it is
           accessed.

           The age is defined in milliseconds.

           Default is 10 timutes.

         mibs_cache_gclimit() = integer() > 0 | infinity <optional>:
           When performing a GC, this is the max number of cache entries  that  will  be  deleted
           from the cache.

           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.

           Default is 100.

         error_report_mod() = atom() <optional>:
           Defines an error report module, implementing  the  snmpa_error_report  behaviour.  Two
           modules are provided with the toolkit: snmpa_error_logger and snmpa_error_io.

           Default is snmpa_error_logger.

         symbolic_store() = [symbolic_store_opt()]:
           symbolic_store_opt() = {verbosity, verbosity()}

           Defines options specific for the SNMP agent symbolic store.

           For defaults see the options in symbolic_store_opt().

         target_cache() = [target_cache_opt()]:
           target_cache_opt() = {verbosity, verbosity()}

           Defines options specific for the SNMP agent target cache.

           For defaults see the options in target_cache_opt().

         agent_config() = [agent_config_opt()] <mandatory>:
           agent_config_opt()   =   {dir,  agent_config_dir()}  |  {force_load,  force_load()}  |
           {verbosity, verbosity()}

           Defines specific config related options for the SNMP agent.

           For defaults see the options in agent_config_opt().

         agent_config_dir = dir() <mandatory>:
           Defines where the SNMP agent configuration files are stored.

         force_load() = bool() <optional>:
           If true the configuration files are re-read during start-up, and the contents  of  the
           configuration  database  ignored. Thus, if true, changes to the configuration database
           are lost upon reboot of the agent.

           Default is false.

       Manager specific config options and types:

         server() = [server_opt()] <optional>:
           server_opt() = {timeout, server_timeout()} | {verbosity, verbosity()}

           Specifies the options for the manager server process.

           Default is silence.

         server_timeout() = integer() <optional>:
           Asynchronous 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 best before time has been passed. This cleanup
           will be performed at regular intervals, defined  by  the  server_timeout()  time.  The
           information  will  have  an  best  before  time, defined by the Expire time given when
           calling the request function (see async_get, async_get_next and async_set).

           Time in milli-seconds.

           Default is 30000.

         manager_config() = [manager_config_opt()] <mandatory>:
           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()}

           Defines specific config related options for the SNMP manager.

           For defaults see the options in manager_config_opt().

         manager_config_dir = dir() <mandatory>:
           Defines where the SNMP manager configuration files are stored.

         manager_db_dir = dir() <mandatory>:
           Defines where the SNMP manager store persistent data.

         manager_repair() = false | true | force <optional>:
           Defines the repair option for the  persistent  database  (if  and  how  the  table  is
           repaired when opened).

           Default is true.

         manager_auto_save() = integer() | infinity <optional>:
           The  auto  save  interval. The table is flushed to disk whenever not accessed for this
           amount of time.

           Default is 5000.

         manager_irb() = auto | user | {user, integer()} <optional>:
           This  option  defines  how  the  manager  will  handle   the   sending   of   response
           (acknowledgment) to received inform-requests.

           * auto  -  The  manager  will  autonomously  send response (acknowledgment> to inform-
             request messages.

           * {user, integer()} - The manager  will  send  response  (acknowledgment)  to  inform-
             request messages when the handle_inform function completes. The integer is the time,
             in milli-seconds, that the manager will  consider  the  stored  inform-request  info
             valid.

           * user  - Same as {user, integer()}, except that the default time, 15 seconds (15000),
             is used.

           See snmpm_network_interface, handle_inform and definition of the manager  net  if  for
           more info.

           Default is auto.

         manager_mibs() = [string()] <optional>:
           Specifies  a list of MIBs (including path) and defines which MIBs are initially loaded
           into the SNMP manager.

           Default is [].

         manager_net_if() = [manager_net_if_opt()] <optional>:
           manager_net_if_opt() = {module, manager_net_if_module()} | {verbosity, verbosity()}  |
           {options, manager_net_if_options()}

           Defines options specific for the SNMP manager network interface entity.

           For defaults see the options in manager_net_if_opt().

         manager_net_if_options() = [manager_net_if_option()] <optional>:
           manager_net_if_option()  =  {bind_to,  bind_to()}  |  {sndbuf,  sndbuf()}  |  {recbuf,
           recbuf()} | {no_reuse, no_reuse()} | {filter, manager_net_if_filter_options()}

           These options are actually specific to the  used  module.  The  ones  shown  here  are
           applicable to the default manager_net_if_module().

           For defaults see the options in manager_net_if_option().

         manager_net_if_module() = atom() <optional>:
           The  module  which  handles  the  network interface part for the SNMP manager. It must
           implement the snmpm_network_interface behaviour.

           Default is snmpm_net_if.

         manager_net_if_filter_options() = [manager_net_if_filter_option()] <optional>:
           manager_net_if_filter_option() = {module, manager_net_if_filter_module()}

           These options are actually specific to the  used  module.  The  ones  shown  here  are
           applicable to the default manager_net_if_filter_module().

           For defaults see the options in manager_net_if_filter_option().

         manager_net_if_filter_module() = atom() <optional>:
           Module  which  handles  the  network  interface filter part for the SNMP manager. Must
           implement the snmpm_network_interface_filter behaviour.

           Default is snmpm_net_if_filter.

         def_user_module() = atom() <optional>:
           The module implementing the default user. See the snmpm_user behaviour.

           Default is snmpm_user_default.

         def_user_data() = term() <optional>:
           Data for the default user. Passed  to  the  user  module  when  calling  the  callback
           functions.

           Default is undefined.

       Common config types:

         restart_type() = permanent | transient | temporary:
           See supervisor documentation for more info.

           Default is permanent for the agent and transient for the manager.

         db_init_error() = terminate | create | create_db_and_dir:
           Defines  what  to  do  if  the agent or manager is unable to open an existing database
           file. terminate means that the agent/manager will terminate and create means that  the
           agent/manager   will   remove   the   faulty   file(s)   and   create  new  ones,  and
           create_db_and_dir means that the agent/manager will create  the  database  file  along
           with any missing parent directories for the database file.

           Default is terminate.

         priority() = atom() <optional>:
           Defines the Erlang priority for all SNMP processes.

           Default is normal.

         versions() = [version()] <optional>:
           version() = v1 | v2 | v3

           Which SNMP versions shall be accepted/used.

           Default is [v1,v2,v3].

         verbosity() = silence | info | log | debug | trace <optional>:
           Verbosity for a SNMP process. This specifies now much debug info is printed.

           Default is silence.

         bind_to() = bool() <optional>:
           If true, net_if binds to the IP address. If false, net_if listens on any IP address on
           the host where it is running.

           Default is false.

         no_reuse() = bool() <optional>:
           If true, net_if does not specify that the IP and port address should be  reusable.  If
           false, the address is set to reusable.

           Default is false.

         recbuf() = integer() <optional>:
           Receive buffer size.

           Default value is defined by gen_udp.

         sndbuf() = integer() <optional>:
           Send buffer size.

           Default value is defined by gen_udp.

         note_store() = [note_store_opt()] <optional>:
           note_store_opt() = {timeout, note_store_timeout()} | {verbosity, verbosity()}

           Specifies the start-up verbosity for the SNMP note store.

           For defaults see the options in note_store_opt().

         note_store_timeout() = integer() <optional>:
           Note cleanup time. When storing a note in the note store, each note is given lifetime.
           Every timeout the note_store process performs a GC to remove the expired note's.  Time
           in milli-seconds.

           Default is 30000.

         audit_trail_log() = [audit_trail_log_opt()] <optional>:
           audit_trail_log_opt()  =  {type, atl_type()} | {dir, atl_dir()} | {size, atl_size()} |
           {repair, atl_repair()} | {seqno, atl_seqno()}

           If present, this option specifies  the  options  for  the  audit  trail  logging.  The
           disk_log  module  is used to maintain a wrap log. If present, the dir and size options
           are mandatory.

           If not present, audit trail logging is not used.

         atl_type() = read | write | read_write <optional>:
           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.

           For the agent:

           * If write is specified, only set requests are logged.

           * If read is specified, only get requests are logged.

           * If read_write, all requests are logged.

           For the manager:

           * If write is specified, only sent messages are logged.

           * If read is specified, only received messages are logged.

           * If read_write, both outgoing and incoming messages are logged.

           Default is read_write.

         atl_dir = dir() <mandatory>:
           Specifies where the audit trail log should be stored.

           If  audit_trail_log  specifies  that logging should take place, this parameter must be
           defined.

         atl_size() = {integer(), integer()} <mandatory>:
           Specifies the size of the audit trail log. This parameter is sent to disk_log.

           If audit_trail_log specifies that logging should take place, this  parameter  must  be
           defined.

         atl_repair() = true | false | truncate | snmp_repair <optional>:
           Specifies  if  and  how the audit trail log shall be repaired when opened. Unless this
           parameter has the value snmp_repair it is sent to disk_log. If, on the other hand, the
           value  is  snmp_repair, 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  moves  it
           aside for later off-line analysis.

           Default is true.

         atl_seqno() = true | false <optional>:
           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.

           Default is false.

SEE ALSO

       application(3erl), disk_log(3erl)