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Interface Description Parsing

Librenms can interpret, display and group certain additional information on ports. This is done based on the format that the port description is written although it's possible to customise the parser to be specific for your setup.


See examples for formats.

  • Keywords
  • Cust - Customer
  • Transit - Transit link
  • Peering - Peering link
  • Core - Infrastructure link (non-customer)
  • Info-keywords
  • () contains a note
  • {} contains your circuit id
  • [] contains the service type or speed



interface Gi0/1
descr Transit: Example Provider (AS65000)
interface Gi0/2
descr Peering: Peering Exchange
interface Gi0/3
descr Core: core.router01 FastEthernet0/0 (Telco X CCID023141)
interface Gi0/4
descr Cust: Example Customer [10Mbit] (T1 Telco Y CCID129031) {EXAMP0001}

Unix / Linux:

This requires an additional script to be setup

# eth3: Cust: Example Customer [10Mbit] (T1 Telco Y CCID129031) {EXAMP0001}
# eth0: Transit: Example Provider (AS65000)
# eth1: Core: core.router01 FastEthernet0/0 (Telco X CCID023141)
# eth2: Peering: Peering Exchange


The following config options can be set to enable more custom types:


lnms config:set customers_descr.+ 'cust'
lnms config:set transit_descr.+ 'transit'
lnms config:set peering_descr.+ 'peering'";'
lnms config:set core_descr.+ 'core'
lnms config:set custom_descr.+ 'something_made_up'

Custom interface parser

It's also possible to write your own parser, the existing one is: includes/

Once you've created your own then you can enable it with:

$config['port_descr_parser'] = "includes/custom/";


For Unix / Linux based systems, you need to run an additional script to support the parsing of interface information.

  • Add ifAlias from /opt/librenms/scripts/ or download it from here to the Server and make it executable chmod +x /path/to/ifAlias
  • Add to snmpd.conf something like: pass . /path/to/ifAlias
  • Add aliasses with
  • iproute2 package like: ip link set eth0.427 alias 'Cust: CustomerA'
  • in /etc/network/interfaces or /etc/network/interfaces.d/* with a comment like: # eth0.427: Cust CustomerA

  • Restart snmpd - systemctl restart snmpd

There are no changes to be made or additions to install for the polling librenms.

Now you can set up your keywords in your aliases.