# snmp

### APPLICATION

snmp

### APPLICATION SUMMARY

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(3) for more information about configuration parameters.

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"}]}]}]}
            ]
           }
          ].

`agent = [agent_opt()]`
  `agent_opt() = {restart_type, restart_type()} | {agent_type, agent_type()} | {agent_verbosity, verbosity()} | {versions, versions()} | {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()} | {config, agent_config()}`
  The SNMP agent specific options.
`manager = [manager_opt()]`
  `manager_opt() = {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_module, def_user_module() | {def_user_data, def_user_data()}`
  The SNMP manager specific options.

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`.
`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.
`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()}`
  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 simultanious requests handled by the agent.
  Default is `infinity`.
`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 allways be loaded:
  - version v1: `STANDARD-MIB`
  - version v2: `SNMPv2`
  - version v3: `SNMPv2`, `SNMP-FRAMEWORK-MIB` and `SNMP-MPD-MIB`
  Default is `[]`.
`mib_storage() = ets | {ets, Dir} | {ets, Dir, Action} | dets | {dets, Dir} | {dets, Dir, Action} | mnesia | {mnesia, Nodes} | {mnesia, Nodes, Action} <optional>`
  Specifies how info retrieved from the mibs will be stored.
  If `mib_storage` is `{ets, Dir}`, the table will also be stored on file. If `Dir` is `default`, then `db_dir` will be used.
  If `mib_storage` is `dets` or if `Dir` is `default`, then `db_dir` will be used for `Dir`.
  If `mib_storage` is `mnesia` then `erlang:nodes()` will be used for `Nodes`.
  Default is `ets`.
  `Dir = default | string()`. Dir is the directory where the files will be stored. If `default`, then `db_dir` will be used.
  `Nodes = visible | connected | [node()]`. `Nodes = visible` is translated to `erlang:nodes(visible)`. `Nodes = connected` is translated to `erlang:nodes(connected)`. If `Nodes = []` then the own node is assumed.
  `Action = clear | keep`. Default is `keep`. `Action` is used to specify what shall be done if the mnesia/dets table already exist.
`mib_server() = [mib_server_opt()] <optional>`
  `mib_server_opt() = {mibentry_override, mibentry_override()} | {trapentry_override, trapentry_override()} | {verbosity, verbosity()}`
  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 perpose 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 perpose of the check is to prevent that the same symbolic trap name is used for different trap's.
  Default is `false`.
`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()`.
`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 startup, 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>`
  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 relpy (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 ag, agn and as).
  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 (acknowledgement) to received inform-requests.
  - `auto` - The manager will autonomously send response (acknowledgement> to inform-request messages.
  - `{user, integer()}` - The manager will send response (acknowledgement) 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()}`
  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>`
  Module which handles the network interface part for the SNMP manager. Must implement the snmpm_network_interface behaviour.
  Default is `snmpm_net_if`.
`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 documentaion for more info.
  Default is `permanent` for the agent and `transient` for the manager.
`db_init_error() = terminate | create`
  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.
  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 adress. 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 startup 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()}`
  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 incomming 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 it's 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`.

### See Also

application(3), disk_log(3)

### AUTHORS

Martin Björklund - support@erlang.ericsson.se

snmp 4.8.2
Copyright © 1991-2006 Ericsson AB