Autodiscovery by IP

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1

I have yet to get autodiscovery using IP to work. This is a new install of LibreNMS.
I have edited config.php setting snmp community = array. Had an issue with that using multiple lines for different communities per the docs so for now just have one line with the predominant community.
I have set [‘nets’] for the allowed networks and set the following;
// Autodiscovery Settings
$config[‘autodiscovery’][‘xdp’] = false;
// Autodiscover hosts via discovery protocols
$config[‘autodiscovery’][‘ospf’] = false;
// Autodiscover hosts via OSPF
$config[‘autodiscovery’][‘bgp’] = false;
// Autodiscover hosts via BGP
$config[‘autodiscovery’][‘snmpscan’] = false;
// autodiscover hosts via SNMP scanning
$config[‘discover_services’] = false;
// Autodiscover services via SNMP on devices of type “server”
// Networks to exclude from autodiscovery
$config[‘autodiscovery’][‘nets-exclude’][] = ‘0.0.0.0/8’;
$config[‘autodiscovery’][‘nets-exclude’][] = ‘127.0.0.0/8’;
$config[‘autodiscovery’][‘nets-exclude’][] = ‘169.254.0.0/16’;
$config[‘autodiscovery’][‘nets-exclude’][] = ‘224.0.0.0/4’;
$config[‘autodiscovery’][‘nets-exclude’][] = ‘240.0.0.0/4’;
// Autodiscover by IP
$config[‘discovery_by_ip’] = true;
// Set to true if you want to enable auto discovery by IP

I ran snmp-scan -d with a network specified and that worked after I removed the multiple communities. That originally appeared to use only the last community listed.
Still no autodiscover by IP. Server has been running since 12/21. Any ideas?

2

You need to allow to autodiscovery to discover you have excluded allot discovery modules only thing is allowed is the discovery by ip and all that does allow a device to be added if cant resolve the DNS name it will try with IP.

Also, You need to specify a network and set the SNMP community strings in config.php

If I were I would allow $config[‘autodiscovery’][‘xdp’] = true;

3

https://docs.librenms.org/#Extensions/Auto-Discovery/

4

Yes, I have been through that and several posts. I didn’t realize I needed one of them true for it to do the IP discovery. I have set xdp to true and will see what happens next time it trys.

Thanks,

tk

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5

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6

Autodiscovery by ip means when the devices are added it uses the IP and not a hostname if one is found.

It does not mean it will scan your IP ranges, that is what snmp-scan.py is for.

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7

Ah, so there is not an automatic scan for devices by say a subnet? If so, unfortunate since I would like it to do a periodic scan for new devices by IP since we do not add everything to dns etc.

tk

8

Not just by subnet, it would need to be discovered using the following. (From the doc)

ARP
XDP: FDP, CDP LLDP
OSPF
BGP

You could use SNMP-scan.py with the properly configured subnets in config.php and run a scan on the subnets you have set.

9

You could always set up a cron to run snmp-scan.py. lldp, etc works great for me though.

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10

iam in a similar position as this poster (we dont use DNS, only IPs), and i kept having issues trying to figure out why auto discovery would not work on the IPs ranges/subnets i had defined. Then i found snmp-scan.py (maybe that should be part of the normal auto discovery, or alteleate an option that can be enabled).

however my question is- is there anyway that LLDP device discovery can be done via the IP address returned via LLDP ? ie (in librenms) my switch sees LLDP data from access points connected to its eth ports, but it tries to scan the APs name (and fails, as we dont use DNS). I know that the devices’ IP address is also in the LLDP packet/data, so id like that to be tried to scan. any what to do this?

tks

11

https://docs.librenms.org/Extensions/Auto-Discovery/#discovering-devices-by-ip## Additional Options

Discovering devices by IP

By default we don’t add devices by IP address, we look for a reverse dns name to be found and add with that. If this fails and you would like to still add devices automatically then you will need to set $config['discovery_by_ip'] = true;

12

Is there an easy possibility to add multiple Devices by IP-Range and mapped SNMP Community Settings? And do this as an auto-discovery?

The documentation only tells about CIDR Networks, and does not include mapped SNMP Community

Example:
Range 1:
Range: 192.168.103.11-192.168.103.23
SNMP Version: v2c
Community: community1

Range 2:
Range: 172.18.10.100-172.18.10.199
SNMP Version: v2c
Community: community2

I prefer to avoid not to access Devices with wrong community, or non-networking Devices in the subnet.