Nagios XI - Receiving IPv6 SNMP Traps


Overview

This KB article explains how to configure Nagios XI to receive SNMP Traps that come in via IPv6 (Internet Protocol version 6).

It is a requirement to have already followed this guide to install all the SNMP Trap pre-requisites:

Documentation - How to Integrate SNMP Traps With Nagios XI

 

 

Editing Files

In many steps of this article you will be required to edit files. This documentation will use the vi text editor. When using the vi
editor:

 

 

Configure SNMPTRAPD

These steps configure snmptrapd to listen for IPv6 traps.

Establish an SSH session to your Nagios XI server as a root user.

Edit the /etc/snmp/snmptrapd.conf file and add the following line:

snmpTrapdAddr    udp:162,udp6:162

Save and close the file.

 

Now restart the SNMPTRAPD service:

RHEL 6 | CentOS 6 | Oracle Linux 6

service snmptrapd restart

 

RHEL 7 | CentOS 7 | Oracle Linux 7 | Debian | Ubuntu 16/18

systemctl restart snmptrapd.service

 

Ubuntu 14

service snmpd restart

 

 

Firewall Rules

You will also need to add a firewall rule allow IPv6 SNMP Traps using one of the commands below:

RHEL 6 | CentOS 6 | Oracle Linux 6

ip6tables -I INPUT -p udp --destination-port 162 -j ACCEPT
service ip6tables save

 

RHEL 7 | CentOS 7 | Oracle Linux 7

firewall-cmd --zone=public --add-port=162/udp
firewall-cmd --zone=public --add-port=162/udp --permanent

 

Debian

iptables -I INPUT -p udp --destination-port 162 -j ACCEPT

 

Ubuntu

ufw allow proto udp from any to any port 162
ufw reload

 

At this point your Nagios XI server will listen for SNMP IPv6 traps (as well as IPv4).

 

 

Update snmptraphandling.py Script

There is currently a bug in how the Net-SNMP libraries spool these received IPv6 traps. In brief, the side affects of this bug are:

Full details about the bug are reported here:

#2704 IPv6 Trap addresses not processed correctly

 

Without going into too much detail about the bug, lets compare the address in an IPv4 trap compared to an IPv6 trap:

 

Once the trap is spooled, it is processed by snmptt (SNMP Trap Translator).

Processed traps are submitted to Nagios using the EXEC statement, which executes the /usr/local/bin/snmptraphandling.py script and passes on the address value.

 

The following modifications to the snmptraphandling.py script allow:

 

Edit the file

/usr/local/bin/snmptraphandling.py

Change this:

host = sys.argv[1]

To this:

host = sys.argv[1]
if host.startswith("UDP/IPv6"):
try:
import socket
host = socket.gethostbyaddr(sys.argv[1].partition('[')[-1].rpartition(']')[0])[0]
#host = host.partition('.')[0]
except:
host = sys.argv[1].partition('[')[-1].rpartition(']')[0]

 

This line here:

                host = socket.gethostbyaddr(sys.argv[1].partition('[')[-1].rpartition(']')[0])[0]

Will result in something like myserver.mydomain.local

 

If you uncomment this line:

                #host = host.partition('.')[0]

The object will be the short version myserver

 

 

Final Thoughts

For any support related questions please visit the Nagios Support Forums at:

http://support.nagios.com/forum/



Article ID: 499
Created On: Thu, Apr 28, 2016 at 1:50 AM
Last Updated On: Tue, Dec 18, 2018 at 5:38 PM
Authored by: tlea

Online URL: https://support.nagios.com/kb/article/nagios-xi-receiving-ipv6-snmp-traps-499.html