Support Trap from Cumulus devices

1

When I generate a linkDown event on Cumulus device, Cumulus send a snap-trap message to LIbreNMS, libreNMS received it ( checked with tcpdump). but the trap is not showed in event log .
This is just basic linkDown event.

What configuration is needed in LibreNMS in order to support trap from Cumulus ?

2

Hi jhfeng,

Did you setup traps? https://docs.librenms.org/Extensions/SNMP-Trap-Handler/

3

Hi @Kevin_Krumm yes, I followed each step. I even downloaded MIBS from Cumulus device and add them into /opt/librenms/mibs/cumulus. my /etc/systemd/system/snmptrapd.service.d/mibs.conf is like this:

[Service]
Environment=MIBDIRS=+/opt/librenms/mibs:/opt/librenms/mibs/arista:/opt/librenms/mibs/cumulus
Environment=MIBS=+ALL

snmptrapd has been reload and restarted.

In fact, the traps from my Atrsta test device is reported correctly.

Is there debug option I can use to check why the trap message is getting lost.

My trap message from Cumulus looks like this in tcpdump:

22:05:17.324746 IP 10.97.65.150.52828 > 10.97.65.60.snmp-trap: F=ap U=“rov3” [!scoped PDU]a7_11_22_c8_85_4c_75_dd_0f_90_29_4e_ca_ed_1e_88_8f_e3_8b_83_25_92_f1_d0_5c_85_2d_84_c8_26_32_b6_bf_64_de_35_03_8f_74_e3_2b_e2_ae_9c_63_50_f5_1e_f5_b8_1b_01_24_0e_60_e2_6b_48_dd_5e_0c_28_1c_2a_84_84_89_1f_e9_d4_2f_f7_c1_e2_67_1b_4f_32_8f_ad_56_cf_eb_18_45_3a_23_45_e1_bd_11_f0_ba_b3_14_f1_d7_b2_7b_60_4c_45_e3_bd_f4_ba_fe_05_97_fc_a7_e2_9b_a8_7e_74_58_66_01_5c_52_c5_0c_46_da_4c_03_2b_e2_79_b5_c4_f7_84_25_9a_27_70_4f_4a_a7_5f_e8_e0_1f_0a_11_e7_28_e4_f3_12_d1_7c_b9_fe_18_1a_a2_07_86_91_d4_a3_b6_5d_3f_6b_40_54_fb_88_39_0d_c2_a1_8d_c5_21_03_f8_8b_4f_5b_fa_8e_fe_ec_83_55_23_d7_6e_d6_57_04_22_be_d2_7b_09_2e_d1_d4_c2_9d_a0_ed_63_d0_cb_f2_23_ba_e1_4f_29_b6_b0_b9_40_f7_10_a0_f6_c4_27_89_56_14_18_70_71_26_61_43_6b_6e_29_5f_0e_44_30_dc_b8_35_7f_be_69_cf_b7_96_b4_e8_9b_22_70_28_52_0d_d1_d3_9e

4

I think you can have it show the generic traps in the event log by enabling a flag.

5

@Kevin_Krumm which flag ? generic trap is what I need at this time

6

this flag https://docs.librenms.org/Extensions/SNMP-Trap-Handler/#event-logging

7

@Kevin_Krumm I already use ‘all’ for this flag:

Default community

$config[‘snmp’][‘community’] = array(“public”);
$config[‘snmptraps’][‘eventlog’] = ‘all’;

syslog

$config[‘enable_syslog’] = 1;

8

For basic linkDown trap, I don’t need add new handler, right ? like documented here https://docs.librenms.org/Developing/SNMP-Traps/

9

I think you do.

10

@Kevin_Krumm so you think the existing /opt/librenms/LibreNMS/Snmptrap/Handlers/LinkDown.php is not good enough for generic linkDown trap ?

11

The old trap handler is bad. I have never missed with the snmp traps.