5.4.8. HOWTO Configure SNMPD

This document details how to use the simp-simp_snmpd Puppet profile module to configure the SNMP daemon.

Simple instructions to configure the snmpd daemon using the simp-simp_snmpd profile module are described in its README file.


simp-simp_snmpd and its dependency puppet-snmp are not core modules and may need to be installed prior to following this guide. SNMPD Configuration

There are two primary configuration directories:

  • /etc/snmp/simp_snmpd.d

    • Files managed by puppet

  • /etc/snmp/user_snmpd.d

    • Files not managed by puppet

    • Extended configurations should be placed here

    • Settings in this directory will override settings in the simp_snmpd.d directory

snmptrapd is disabled by default. The daemon can be enabled, but pupmod-simp-simp_snmpd will not configure it. If you need to run snmptrapd, set simp_snmpd::trap_service_ensure and simp_snmpd::trap_service_startatboot appropriately, and place any configuration files in /etc/snmp/user_trapd.d, with a .conf extension. Agent Addresses and Firewall

By default, simp-simp_snmpd configures snmpd to listen on the local interface. Use simp_snmpd::agentaddress to toggle what interfaces snmpd will listen on.


simp_snmpd::agentaddress is an array of strings that should follow the format defined in the man page for snmpd, under the LISTENING ADDRESS section.

The following is an example agent address:

  - upd:161
  - tcp:%{facts.fqdn}:161

If simp_options::firewall is turned on, simp-simp_snmpd will parse the array of listening addresses to determine what ports should be opened. It does not, at this time, do anything for ipx or pvc. simp_snmpd::trusted_nets is used to determine what networks can access the ports.


If the agent address is set in a conf file in the user directory, but not in Hiera or in the simp_snmpd resource call, simp-simp_snmpd will not open the ports in the firewall. Access

simp-simp_snmpd configures SNMP v3, with

  • User-based Security Model (USM)

  • View-based Access Control Model (VACM).

The profile module, by default, installs two users:

  • snmp_ro is configured for read only access to system view

  • snmp_rw is configured for read/write access to everything

User passwords are auto-generated using simplib::passgen() and stored on the SIMP Server in a sub-directory in the SIMP Writable Environment:


Access is configured by /etc/snmp/simp_snmpd.d/access.conf

  • To create the access.conf file, the profile modules uses a set of hashes.

  • The default hashes are in the data/common.yaml file.

  • These hashes are merged with any hash you defined in the Hiera files on the Puppet Server. Merging is described in Puppet docs

  • To remove something from the default hash add the name of object with no keys


To remove a user, or modify their password, the snmpusm utility must be used, or remove /var/lib/net-simp and run puppet. Changing the password in the hash or removing the keys will not change the password of an existing user.

Example hashes used to create users, views, group and give access: User Hash

    authtype: MD5|SHA
    privtype: DES|AES
    privpass: 'your priv password'
    authpass: 'your auth password'
  • If authtype or privtype is missing, it will use the modules $defauthtype and $defprivtype

  • If either of the passwords are missing, it will be automatically generated using simplib::passgen() View Hash

    included: [array of OIDs to include]
    excluded: [array of OIDs to exclude]
  • One or both of included, excluded needs to be specified. Any number of OIDs can be listed

  • It will create one view line for each OID in the list with exclude or include Group Hash

    model: The security model to use (default to defsecuritymodel)
    secname: [array of user names to include in this group]
  • It does not verify the user exists Access Hash

    vread: view to use for reading access (default none)
    vwrite: view to use for write access (default none)
    vnotify: view to use for notify (default none)
    level:  priv|auth|noauth (default is defsecuritylevel)
    model: the model to use (default is defsecuritymodel)
    context: context to use (default "")
    prefix:  prefix for the context exact| prefix (default exact)
    groups: [array of groups to create this access for]
  • It does not verify the group exists

  • The access name is just a place holder

  • For all hashes, anything with a default does not need to be included in the hash


Any views, groups, or access lines set up in user conf files will be in addition to anything configured in the hash. Remove Values from Default Hash

If you do not want the default user, or any of the views, groups, or access created, you can pass and empty hash and it will ignore that setting:

    authpass: 'HardToBreakPassword'
    privpass: 'OtherPassword'
    secname: myuser
  • The above example will not create the snmp_ro user and add myuser. If the snmp_ro user is already created it will not delete it.

  • It will override the default definition of readonly_group

  • The quickest way to delete users or change the password is to configure the hashes and the remove the /var/lib/net-simp directory, stop the snmpd daemon, and run puppet. Client

By default, the net-snmp-utils package is not installed, so snmpd utilities such as snmpget, snmpset, and snmpwalk will not be available. Set simp_snmpd::manage_client to true to install the package.

simp_snmpd::manage_client: true


After installation, the default security model, level, authentication, and privacy types will be configured. No default passwords will be configured. Rsync MIBS and DLMODS

Rsync can be used to push out custom MIBS and dynamically loaded shared objects, or dlmod.

By default, rsync will copy MIBS into the directory used by net-snmp. To copy them elsewhere, set simp_snmpd::rsync_mibs_dir to the fully qualified path.


The module will rsync the files to a MIBS directory under that path and add the directory to the MIBS path.

DLMODS are copied the same way as MIBS, using the rsync_dlmod_dir as the destination, creating a dlmod directory. In order to load dlmods, you must add the name of the module to the simp_snmpd::dlmods list. This will create a dlmod.conf file in simp_snmpd. The .so extension will be added. See the Dynamically Loadable Modules section in man page of snmpd.conf for more information.

Below is an example showing how to activate rsync of MIBS and dlmods:

simp_snmpd::rsync_dlmod: true
simp_snmpd::rsync_mibs: true
  - mymodulename