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Configuration Docs

LibreNMS configuration is a set of key values.

The config is stored in two places: Database: This applies to all pollers and can be set with either lnms config:set or in the Web UI. Database config takes precedence over config.php. config.php: This applies to the local poller only. Configs set here will be disabled in the Web UI to prevent unexpected behaviour.

The LibreNMS uses dot notation for config items:

Database config.php $config['snmp']['community'] $config['snmp']['community'][]
snmp.v3.0.authalgo $config['snmp']['v3'][0]['authalgo']

The documentation has not been updated to reflect using lnms config:set to set config items, but it will work for all settings. Not all settings have been defined in LibreNMS, but they can still be set with the --ignore-checks option. Without that option input is checked for correctness, that does not mean it is not possible to set bad values. Please report missing settings.


lnms config:get will fetch the current config settings (composite of database, config.php, and defaults).
lnms config:set will set the config setting in the database. Calling lnms config:set on a setting with no value will reset it to the default value.

If you set up bash completion, you can use tab completion to find config settings.


lnms config:get
  array (
    0 => 'public',

lnms config:set testing

lnms config:get
  array (
    0 => 'public',
    1 => 'testing',

lnms config:set private

lnms config:get
  array (
    0 => 'private',
    1 => 'testing',

lnms config:set test
  Invalid format

lnms config:set '["test", "othercommunity"]'

lnms config:get
  array (
    0 => 'test',
    1 => 'othercommunity',

lnms config:set

  Reset to the default? (yes/no) [no]:
  > yes

lnms config:get --json


$config['temp_dir'] = "/tmp";

The temporary directory is where images and other temporary files are created on your filesystem.

$config['log_dir'] = "/opt/librenms/logs";

Log files created by LibreNMS will be stored within this directory.

Database config

Set these variables either in .env or in the environment.


Use non-standard port:


Use a unix socket:



PHP Settings

You can change the memory limits for php within config.php. The value is in Megabytes and should just be an int value:

$config['php_memory_limit'] = 128;


A lot of these are self explanatory so no further information may be provided. Any extensions that have dedicated documentation page will be linked to rather than having the config provided.


You can configure these options within the WebUI now, please avoid setting these options within config.php

Settings -> External Settings -> RRDTool Setup

$config['rrdtool'] = "/usr/bin/rrdtool";

Please see 1 Minute polling for information on configuring your install to record data more frequently.


$config['fping']                     = "/usr/bin/fping";
$config['fping6']                    = "fping6";
$config['fping_options']['timeout']  = 500;
$config['fping_options']['count']    = 3;
$config['fping_options']['interval'] = 500;

fping configuration options:

  • timeout (fping parameter -t): Amount of time that fping waits for a response to its first request (in milliseconds). See note below
  • count (fping parameter -c): Number of request packets to send to each target.
  • interval (fping parameter -p): Time in milliseconds that fping waits between successive packets to an individual target.

NOTE: Setting a higher timeout value than the interval value can lead to slowing down poller. Example:

timeout: 3000

count: 3

interval: 500

In this example, interval will be overwritten by the timeout value of 3000 which is 3 seconds. As we send three icmp packets (count: 3), each one is delayed by 3 seconds which will result in fping taking > 6 seconds to return results.

You can disable the fping / icmp check that is done for a device to be determined to be up on a global or per device basis. We don't advise disabling the fping / icmp check unless you know the impact, at worst if you have a large number of devices down then it's possible that the poller would no longer complete in 5 minutes due to waiting for snmp to timeout.

Globally disable fping / icmp check:

$config['icmp_check'] = false;

If you would like to do this on a per device basis then you can do so under Device -> Edit -> Misc -> Disable ICMP Test? On


LibreNMS uses traceroute / traceroute6 to record debug information when a device is down due to icmp AND you have $config['debug']['run_trace'] = true; set.

$config['traceroute']  = '/usr/bin/traceroute';
$config['traceroute6'] = '/usr/bin/traceroute6';


$config['snmpwalk']         = "/usr/bin/snmpwalk";
$config['snmpget']          = "/usr/bin/snmpget";
$config['snmpbulkwalk']     = "/usr/bin/snmpbulkwalk";

SNMP program locations.

$config['whois']            = "/usr/bin/whois";
$config['ping']             = "/bin/ping";
$config['mtr']              = "/usr/bin/mtr";
$config['nmap']             = "/usr/bin/nmap";
$config['nagios_plugins']   = "/usr/lib/nagios/plugins";
$config['ipmitool']         = "/usr/bin/ipmitool";
$config['virsh']            = "/usr/bin/virsh";
$config['dot']              = "/usr/bin/dot";
$config['unflatten']        = "/usr/bin/unflatten";
$config['neato']            = "/usr/bin/neato";
$config['sfdp']             = "/usr/bin/sfdp";


Generic Authentication settings.

$config['password']['min_length'] = 8;  // password minimum length for auth that allows user creation

Proxy support

For alerting and the callback functionality, we support the use of a http proxy setting. These can be any one of the following:

$config['callback_proxy'] = '';
$config['http_proxy']     = '';

We can also make use of one of these environment variables which can be set in /etc/environment:


Please refer to RRDCached

WebUI Settings

$config['base_url'] = "";

LibreNMS will attempt to detect the URL you are using but you can override that here.

$config['site_style']       = "light";

Currently we have a number of styles which can be set which will alter the navigation bar look. dark, light and mono with light being the default.

$config['webui']['custom_css'][]       = "css/custom/styles.css";

You can override a large number of visual elements by creating your own css stylesheet and referencing it here, place any custom css files into html/css/custom so they will be ignored by auto updates. You can specify as many css files as you like, the order they are within your config will be the order they are loaded in the browser.

$config['title_image'] = "images/custom/yourlogo.png";

You can override the default logo with yours, place any custom images files into html/images/custom so they will be ignored by auto updates.

$config['page_refresh']     = "300";

Set how often pages are refreshed in seconds. The default is every 5 minutes. Some pages don't refresh at all by design.

$config['front_page']       = "default";

You can create your own front page by adding a blade file in resources/views/overview/custom/ and setting front_page to it's name. For example, if you create resources/views/overview/custom/foobar.blade.php, set front_page to foobar.

// This option exists in the web UI, edit it under Global Settings -> webui
$config['webui']['default_dashboard_id'] = 0;

Allows the specification of a global default dashboard page for any user who has not set one in their user preferences. Should be set to dashboard_id of an existing dashboard that is shared or shared(read). Otherwise, the system will automatically create each user an empty dashboard called Default on their first login.

$config['login_message']    = "Unauthorised access or use shall render the user liable to criminal and/or civil prosecution.";

This is the default message on the login page displayed to users.

$config['public_status']    = false;

If this is set to true then an overview will be shown on the login page of devices and the status.

$config['show_locations']          = 1;  # Enable Locations on menu
$config['show_locations_dropdown'] = 1;  # Enable Locations dropdown on menu
$config['show_services']           = 0;  # Enable Services on menu
$config['int_customers']           = 1;  # Enable Customer Port Parsing
$config['summary_errors']          = 0;  # Show Errored ports in summary boxes on the dashboard
$config['customers_descr']         = 'cust';  # The description to look for in ifDescr. Can be an array as well array('cust','cid');
$config['transit_descr']           = 'transit';  # Add custom transit descriptions (can be an array)
$config['peering_descr']           = 'peering';  # Add custom peering descriptions (can be an array)
$config['core_descr']              = 'core';  # Add custom core descriptions (can be an array)
$config['custom_descr']            = '';  # Add custom interface descriptions (can be an array)
$config['int_transit']             = 1;  # Enable Transit Types
$config['int_peering']             = 1;  # Enable Peering Types
$config['int_core']                = 1;  # Enable Core Port Types
$config['int_l2tp']                = 0;  # Enable L2TP Port Types

Enable / disable certain menus from being shown in the WebUI.

You are able to adjust the number and time frames of the quick select time options for graphs and the mini graphs shown per row.

Quick select:

$config['graphs']['mini']['normal'] = array(
    'day' => '24 Hours',
    'week' => 'One Week',
    'month' => 'One Month',
    'year' => 'One Year',
$config['graphs']['mini']['widescreen'] = array(
    'sixhour' => '6 Hours',
    'day' => '24 Hours',
    'twoday' => '48 Hours',
    'week' => 'One Week',
    'twoweek' => 'Two Weeks',
    'month' => 'One Month',
    'twomonth' => 'Two Months',
    'year' => 'One Year',
    'twoyear' => 'Two Years',

Mini graphs:

$config['graphs']['row']['normal'] = array(
    'sixhour' => '6 Hours',
    'day' => '24 Hours',
    'twoday' => '48 Hours',
    'week' => 'One Week',
    'twoweek' => 'Two Weeks',
    'month' => 'One Month',
    'twomonth' => 'Two Months',
    'year' => 'One Year',
    'twoyear' => 'Two Years',
$config['web_mouseover']      = true;

You can disable the mouseover popover for mini graphs by setting this to false.

$config['enable_lazy_load'] = true;

You can disable image lazy loading by setting this to false.

$config['show_overview_tab'] = true;

Enable or disable the overview tab for a device.

$config['overview_show_sysDescr'] = true;

Enable or disable the sysDescr output for a device.

$config['force_ip_to_sysname'] = false;

When using IP addresses as a hostname you can instead represent the devices on the WebUI by its SNMP sysName resulting in an easier to read overview of your network. This would apply on networks where you don't have DNS records for most of your devices.

$config['force_hostname_to_sysname'] = false;

When using a dynamic DNS hostname or one that does not resolve, this option would allow you to make use of the SNMP sysName instead as the preferred reference to the device.

$config['device_traffic_iftype'][] = '/loopback/';

Interface types that aren't graphed in the WebUI. The default array contains more items, please see misc/config_definitions.json for the full list.

$config['enable_clear_discovery'] = 1;

Administrators are able to clear the last discovered time of a device which will force a full discovery run within the configured 5 minute cron window.

$config['enable_footer'] = 1;

Disable the footer of the WebUI by setting enable_footer to 0.

You can enable the old style network map (only available for individual devices with links discovered via xDP) by setting:

$config['gui']['network-map']['style'] = 'old';
$config['percentile_value'] = X;

Show the Xth percentile in the graph instead of the default 95th percentile.

$config['shorthost_target_length'] = X;

The target maximum hostname length when applying the shorthost() function. You can increase this if you want to try and fit more of the hostname in graph titles. The default value is 12 However, this can possibly break graph generation if this is very long.

You can enable dynamic graphs within the WebUI under Global Settings -> Webui Settings -> Graph Settings.

Graphs will be movable/scalable without reloading the page: Example dynamic graph usage

Stacked Graphs

You can enable stacked graphs instead of the default inverted graphs. Enabling them is possible via webui Global Settings -> Webui Settings -> Graph settings -> Use stacked graphs

Add host settings

The following setting controls how hosts are added. If a host is added as an ip address it is checked to ensure the ip is not already present. If the ip is present the host is not added. If host is added by hostname this check is not performed. If the setting is true hostnames are resolved and the check is also performed. This helps prevents accidental duplicate hosts.

$config['addhost_alwayscheckip']   = false; # true - check for duplicate ips even when adding host by name.
                                            # false- only check when adding host by ip.

By default we allow hosts to be added with duplicate sysName's, you can disable this with the following config:

$config['allow_duplicate_sysName'] = false;

Global poller and discovery modules

Generally, it is a better to set these per OS or device.

$config['discovery_modules']['arp-table'] = true;
$config['poller_modules']['bgp-peers']    = false;

SNMP Settings

Default SNMP options including retry and timeout settings and also default version and port.

$config['snmp']['timeout'] = 1;                         # timeout in seconds
$config['snmp']['retries'] = 5;                         # how many times to retry the query
$config['snmp']['transports'] = ['udp', 'udp6', 'tcp', 'tcp6'];    # Transports to use
$config['snmp']['version'] = ['v2c', 'v3', 'v1'];       # Default versions to use
$config['snmp']['port'] = 161;                          # Default port
$config['snmp']['exec_timeout'] = 1200;                 # execution time limit in seconds

NOTE: timeout is the time to wait for an answer and exec_timeout is the max time to run a query.

The default v1/v2c snmp community to use, you can expand this array with [1], [2], [3], etc.

$config['snmp']['community'][0] = "public";

NOTE: This list of SNMP communities is used for auto discovery, and as a default set for any manually added device.

The default v3 snmp details to use, you can expand this array with [1], [2], [3], etc.

$config['snmp']['v3'][0]['authlevel'] = "noAuthNoPriv";  # noAuthNoPriv | authNoPriv | authPriv
$config['snmp']['v3'][0]['authname'] = "root";           # User Name (required even for noAuthNoPriv)
$config['snmp']['v3'][0]['authpass'] = "";               # Auth Passphrase
$config['snmp']['v3'][0]['authalgo'] = "MD5";            # MD5 | SHA
$config['snmp']['v3'][0]['cryptopass'] = "";             # Privacy (Encryption) Passphrase
$config['snmp']['v3'][0]['cryptoalgo'] = "AES";          # AES | DES

Auto discovery settings

Please refer to Auto-Discovery

Email configuration

You can configure these options within the WebUI now, please avoid setting these options within config.php

$config['email_backend']              = 'mail';
$config['email_from']                 = NULL;
$config['email_user']                 = $config['project_id'];
$config['email_sendmail_path']        = '/usr/sbin/sendmail';
$config['email_smtp_host']            = 'localhost';
$config['email_smtp_port']            = 25;
$config['email_smtp_timeout']         = 10;
$config['email_smtp_secure']          = NULL;
$config['email_smtp_auth']            = false;
$config['email_smtp_username']        = NULL;
$config['email_smtp_password']        = NULL;

What type of mail transport to use for delivering emails. Valid options for email_backend are mail, sendmail or smtp. The varying options after that are to support the different transports.


Please refer to Alerting


Please refer to Billing

Global module support

$config['enable_bgp']                   = 1; # Enable BGP session collection and display
$config['enable_syslog']                = 0; # Enable Syslog
$config['enable_inventory']             = 1; # Enable Inventory
$config['enable_pseudowires']           = 1; # Enable Pseudowires
$config['enable_vrfs']                  = 1; # Enable VRFs
$config['enable_sla']                   = 0; # Enable Cisco SLA collection and display

Port extensions

Please refer to Port-Description-Parser

$config['enable_ports_etherlike']       = 0;
$config['enable_ports_junoseatmvp']     = 0;
$config['enable_ports_adsl']            = 1;
$config['enable_ports_poe']             = 0;

Enable / disable additional port statistics.

External integration


$config['rancid_configs'][]             = '/var/lib/rancid/network/configs/';
$config['rancid_repo_type']             = 'svn';
$config['rancid_ignorecomments']        = 0;

Rancid configuration, rancid_configs is an array containing all of the locations of your rancid files. Setting rancid_ignorecomments will disable showing lines that start with #


Please refer to Oxidized


$config['collectd_dir']                 = '/var/lib/collectd/rrd';

Specify the location of the collectd rrd files. Note that the location in config.php should be consistent with the location set in /etc/collectd.conf and etc/collectd.d/rrdtool.conf

<Plugin rrdtool>
        DataDir "/var/lib/collectd/rrd"
        CreateFilesAsync false
        CacheTimeout 120
        CacheFlush   900
        WritesPerSecond 50


LoadPlugin rrdtool
<Plugin rrdtool>
       DataDir "/var/lib/collectd/rrd"
       CacheTimeout 120
       CacheFlush   900


$config['collectd_sock']                 = 'unix:///var/run/collectd.sock';

Specify the location of the collectd unix socket. Using a socket allows the collectd graphs to be flushed to disk before being drawn. Be sure that your web server has permissions to write to this socket.


Please refer to Smokeping


Please refer to NFSen

Location mapping

If you just want to set GPS coordinates on a location, you should visit Devices > Geo Locations > All Locations and edit the coordinates there.

Exact Matching:

$config['location_map']['Under the Sink'] = "Under The Sink, The Office, London, UK";

Regex Matching:

$config['location_map_regex']['/Sink/'] = "Under The Sink, The Office, London, UK";

Regex Match Substitution:

$config['location_map_regex_sub']['/Sink/'] = "Under The Sink, The Office, London, UK [lat, long]";

If you have an SNMP SysLocation of "Rack10,Rm-314,Sink", Regex Match Substition yields "Rack10,Rm-314,Under The Sink, The Office, London, UK [lat, long]". This allows you to keep the SysLocation string short and keeps Rack/Room/Building information intact after the substitution.

The above are examples, these will rewrite device snmp locations so you don't need to configure full location within snmp.

Interfaces to be ignored

Interfaces can be automatically ignored during discovery by modifying bad_if* entries in a default array, unsetting a default array and customizing it, or creating an OS specific array. The preferred method for ignoring interfaces is to use an OS specific array. The default arrays can be found in misc/config_definitions.json. OS specific definitions (includes/definitions/_specific_os_.yaml) can contain bad_if* arrays, but should only be modified via pull-request as manipulation of the definition files will block updating:


Add entries to default arrays

$config['bad_if'][] = "voip-null";
$config['bad_iftype'][] = "voiceEncap";
$config['bad_if_regexp'][] = '/^lo[0-9].*/';    // loopback

Unset and customize a default array

$config['bad_if'][] = "voip-null";
$config['bad_if'][] = "voiceEncap";
$config['bad_if'][] = "voiceFXO";

Create an OS specific array

$config['os']['iosxe']['bad_iftype'][] = "macSecControlledIF";
$config['os']['iosxe']['bad_iftype'][] = "macSecUncontrolledIF";

Various bad_if* selection options available

bad_if is matched against the ifDescr value.

bad_iftype is matched against the ifType value.

bad_if_regexp is matched against the ifDescr value as a regular expression.

bad_ifname_regexp is matched against the ifName value as a regular expression.

bad_ifalias_regexp is matched against the ifAlias value as a regular expression.

Interfaces that shouldn't be ignored


$config['good_if'][] = 'FastEthernet';
$config['os']['ios']['good_if'][] = 'FastEthernet';

good_if is matched against ifDescr value. This can be a bad_if value as well which would stop that port from being ignored. i.e. if bad_if and good_if both contained FastEthernet then ports with this value in the ifDescr will be valid.

Interfaces to be rewritten

$config['rewrite_if']['cpu'] = 'Management Interface';
$config['rewrite_if_regexp']['/cpu /'] = 'Management ';

Entries defined in rewrite_if are being replaced completely. Entries defined in rewrite_if_regexp only replace the match. Matches are compared case-insensitive.

Entity sensors to be ignored

Some devices register bogus sensors as they are returned via SNMP but either don't exist or just don't return data. This allows you to ignore those based on the descr field in the database. You can either ignore globally or on a per os basis.

$config['bad_entity_sensor_regex'][] = '/Physical id [0-9]+/';
$config['os']['cisco']['bad_entity_sensor_regex'] = '/Physical id [0-9]+/';

Entity sensors limit values

Vendors may give some limit values (or thresholds) for the discovered sensors. By default, when no such value is given, both high and low limit values are guessed, based on the value measured during the initial discovery.

When it is preferred to have no high and/or low limit values at all if these are not provided by the vendor, the guess method can be disabled:

$config['sensors']['guess_limits'] = false;

Ignoring Health Sensors

It is possible to filter some sensors from the configuration:

  • Ignore all temperature sensors
$config['disabled_sensors']['current'] = true;
  • Filter all sensors matching regexp '/PEM Iout/'.
$config['disabled_sensors_regex'][] = '/PEM Iout/';
  • Filter all 'current' sensors for Operating System 'vrp'.
$config['os']['vrp']['disabled_sensors']['current'] = true;
  • Filter all sensors matching regexp '/PEM Iout/' for Operating System iosxe.
$config['os']['iosxe']['disabled_sensors_regex'][] = '/PEM Iout/';

Storage configuration

Mounted storage / mount points to ignore in discovery and polling.

$config['ignore_mount_removable']  = 1;
$config['ignore_mount_network']    = 1;
$config['ignore_mount_optical']    = 1;

$config['ignore_mount'][] = "/kern";
$config['ignore_mount'][] = "/mnt/cdrom";
$config['ignore_mount'][] = "/proc";
$config['ignore_mount'][] = "/dev";

$config['ignore_mount_string'][] = "packages";
$config['ignore_mount_string'][] = "devfs";
$config['ignore_mount_string'][] = "procfs";
$config['ignore_mount_string'][] = "UMA";
$config['ignore_mount_string'][] = "MALLOC";

$config['ignore_mount_regexp'][] = "/on: \/packages/";
$config['ignore_mount_regexp'][] = "/on: \/dev/";
$config['ignore_mount_regexp'][] = "/on: \/proc/";
$config['ignore_mount_regexp'][] = "/on: \/junos^/";
$config['ignore_mount_regexp'][] = "/on: \/junos\/dev/";
$config['ignore_mount_regexp'][] = "/on: \/jail\/dev/";
$config['ignore_mount_regexp'][] = "/^(dev|proc)fs/";
$config['ignore_mount_regexp'][] = "/^\/dev\/md0/";
$config['ignore_mount_regexp'][] = "/^\/var\/dhcpd\/dev,/";
$config['ignore_mount_regexp'][] = "/UMA/";

Custom storage warning percentage

$config['storage_perc_warn'] = 60;
$config['os']['linux']['storage_perc_warn'] = 60;


Please refer to IRC Bot


Please refer to Authentication

Cleanup options

Please refer to Cleanup Options

Syslog options

Please refer to Syslog


$config['enable_libvirt'] = 1;
$config['libvirt_protocols']    = array("qemu+ssh","xen+ssh");
$config['libvirt_username'] = 'root';

Enable this to switch on support for libvirt along with libvirt_protocols to indicate how you connect to libvirt. You also need to:

  1. Generate a non-password-protected ssh key for use by LibreNMS, as the user which runs polling & discovery (usually librenms).
  2. On each VM host you wish to monitor:
  3. Configure public key authentication from your LibreNMS server/poller by adding the librenms public key to ~root/.ssh/authorized_keys.
  4. (xen+ssh only) Enable libvirtd to gather data from xend by setting (xend-unix-server yes) in /etc/xen/xend-config.sxp and restarting xend and libvirtd.

To test your setup, run virsh -c qemu+ssh://vmhost/system list or virsh -c xen+ssh://vmhost list as your librenms polling user.

BGP Support

$config['astext']['65332'] = "Cymru FullBogon Feed";

You can use this array to rewrite the description of ASes that you have discovered.

Auto updates

Please refer to Updating


Setup the types of IPMI protocols to test a host for and in what order. Don't forget to install ipmitool on the monitoring host.

$config['ipmi']['type'] = array();
$config['ipmi']['type'][] = "lanplus";
$config['ipmi']['type'][] = "lan";
$config['ipmi']['type'][] = "imb";
$config['ipmi']['type'][] = "open";

Distributed poller settings

Please refer to Distributed Poller

API Settings

CORS Support

CORS support for the API is disabled by default. Below you will find the standard options, all of which you can configure.

$config['api']['cors']['enabled'] = false;
$config['api']['cors']['origin'] = ['*'];
$config['api']['cors']['maxage'] = '86400';
$config['api']['cors']['allowmethods'] = ['POST', 'GET', 'PUT', 'DELETE', 'PATCH'];
$config['api']['cors']['allowheaders'] = ['Origin', 'X-Requested-With', 'Content-Type', 'Accept', 'X-Auth-Token'];
$config['api']['cors']['exposeheaders'] = ['Cache-Control', 'Content-Language', 'Content-Type', 'Expires', 'Last-Modified', 'Pragma'];
$config['api']['cors']['allowcredentials'] = false;