In this example, we use a Cisco switch (SF300-24P) to send SNMP traps to our Zabbix server. We’ll install a zabbix_trap_receiver.pl (perl script) on Zabbix server in order to process the SNMP traps.

Enable SNMP Traps On Cisco Switch

enable
conf t
snmp-server enable traps
snmp-server host <zabbix server ip> version 2c <your community string>
exit
copy run start

You can verify your SNMP config with:

show snmp

Enable SNMP On Cisco Switch

enable
conf t

Use the below command if you wish to add a Read-Only community string:

snmp-server community public RO

(where “public” is the Read-only community string)

Use the below command if you wish to add a Read-Write community string:

snmp-server community private RW

(where “private” is the Read-write community string)

Exit the configuration mode and save the settings with ->

exit
write memory

Bonus SNMP Commands

Disable SNMP:

 no snmp server

Check SNMP status:

show snmp server

Re-enable SNMP:

snmp server

Set Up Your Zabbix Server To Receive And Process SNMP Traps

Step 1 – Ensure Port 162 Is Open On Your Zabbix Server

If the Linux distro you’re running Zabbix on has port 162 blocked, you will need to open it as SNMP traps are typically sent on port 162.

For Ubuntu, Rspbian, Debian distros you can try this cmd to open port 162

iptables -A INPUT -p udp --dport 162 -J ACCEPT
sudo service iptables restart

For Centos, you can try these cmd’s:

firewall-cmd --add-port=162/udp --permanent
firewall-cmd --reload

If you can’t get the ports opened with those commands, ask ChatGPT

Step 2 – Enable And Configure SNMP Traps On Your Device
(using a Cisco switch in my case as outlined in the beginning of this blog)

Step 3 – Edit Zabbix Server Config

sudo vim /etc/zabbix/zabbix_server.conf

Comment out log file path like so: #SNMPTrapperFile=/var/log/snmptrap.log
Since we will be using the tmp path, you need to uncomment (remove the hashtag) ‘SNMPTrapperFile=/tmp/zabbix_traps.tmp’

Turn on SNMP Trapper by removing the hastag and changing 0 to 1 like so:
StartSNMPTrapper=1

Step 4 – Install zabbix_trap_receiver.pl File To /usr/bin

sudo wget https://git.zabbix.com/projects/ZBX/repos/zabbix/raw/misc/snmptrap/zabbix_trap_receiver.pl -O /usr/bin/zabbix_trap_receiver.pl

If you’re having trouble using the wget command to get the perl script, you can download the zabbix_trap_receiver.pl (perl script) directly from us here and we can get it on the server another way.

Recommend you stick the file on your desktop so you can conveniently copy it up to your Zabbix server in the next coming steps.

From windows cmd line and copy the file up to your Zabbix server with SCP:

scp "C:\Users\reasonableit\Desktop\zabbix_trap_receiver.pl" reasonableit@172.16.10.4:~

(you will need to replace the bolded text of that command with your own unique information, such as username and your zabbix server IP)

Now we need to move the file to the correct directory.
ssh to your Linux/Zabbix server and run this cmd

sudo mv ~/zabbix_trap_receiver.pl /usr/bin/zabbix_trap_receiver.pl

Step 5 – Set Permissions For The Perl Script
Run this cmd from your Linux/Zabbix server

sudo chmod a+x /usr/bin/zabbix_trap_receiver.pl

Step 6 –  Install snmptrapd On Your Zabbix Server

sudo apt install snmp snmp-mibs-downloader snmptrapd

Step 7 – Edit snmptrapd.conf File

sudo vim /etc/snmp/snmptrapd.conf

Add these two lines to bottom of config file with your correct community string (change ‘public’ to your community string):

authCommunity execute <your community string>
perl do “/usr/bin/zabbix_trap_receiver.pl”;

Step 8 – Install libssnmp-perl 
Perl is often missing in modern Linux distributions so we will need to install it with this command:

sudo apt-get install libsnmp-perl

Step 9 – Restart Zabbix Server & snmptrapd Services

sudo service zabbix-server restart

sudo service snmptrapd restart

sudo zabbix_server -R config_cache_reload

Step 10 – Add the host to Zabbix Frontend
Refer to video for details but basically, just add your switch with an SNMP template, generate an snmp trap (WR command on Cisco switch should generate one) and check the SNMP Trap (fallback) item of your device in Zabbix.

Note – You will add your device just like any normal SNMP monitored device with an SNMP template, you do not need to change the port to 162 (what the switch sends snmp traps out on) as the perl script and the Zabbix snmp Trap (fallback) item will handle the snmp trap processing for you. You just need to make sure port 162 is open on your Zabbix server.

Bonus

Zabbix SNMP Trap Documentation

You should also be able to send test traps from your Zabbix server to itself with the following cmd

snmptrap -v2c -cpublic 172.16.10.4 '' .1.3.6.1.6.3.1.1.5.3 .1.3.6.1.6.3.1.1.5.3 s "test trap v2c"

#how to setup SNMP traps in Zabbix 6.4
#how to enable snmp traps on Cisco Switch and monitor with Zabbix 6.4