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Step-by-step guide

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SNMPTRAP

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Steps

1. First you want to install snmptrapd. I also recommend going ahead and enabling snmptrapd to start automatically in case of server reboots

   Code Block
   language bash title Install snmptrapd
   apt-get install snmptrapd systemctl enable snmptrapd

   
   

2. With NET-SNMP Version 5.8 and systemd you will need to override snmptrapd.service. This means that when starting snmptrapd the options you put in the override file will be what starts and not what snmptrapd defaults with.

   Code Block
   language bash title Edit snmptrapd service
   systemctl edit snmptrapd

   
   

3. In the edit window that appears you will want to paste the below text. Editor is nano, I recommend using the default file name so you just need to save and exit (ctl+o, ctl+w)

   Code Block
   language text title override.conf text
   [Service] ExecStart= ExecStart=/usr/sbin/snmptrapd -f -n -OQ -Ls2 -m ALL -M /usr/local/nmis9/mibs/trap

   

4. Edit the /etc/default/snmptrapd file, replacing default TRAPDOTS with the below:

   Code Block
   language bash title edit snmptrapd
   vi /etc/default/snmptrapd

   
   

   Code Block
   language text title /etc/default/snmptrapd
   TRAPDOPTS='-n -LS2d -p /var/run/snmptrapd.pid -m ALL -M /usr/local/nmis9/mibs/traps' TRAPDRUN=yes

   
   

5. Edit the /etc/snmp/snmptrapd.conf file,

   
   

   Code Block
   language bash title edit snmptrapd.conf
   vi /etc/snmp/snmptrapd.conf

   
   

   Code Block
   language text title /etc/snmp/snmptrapd.conf
   disableAuthorization yes #If you have installed nmis9 in a different directory make sure to change below to match. traphandle default /usr/local/nmis9/bin/traplog.pl

   
   

6. Now we need to reload the daemon and restart the service.

   
   

   Code Block
   language bash title reload daemons
   systemctl daemon-reload systemctl restart snmptrapd # Always a good idea to check status systemctl status snmptrapd

   
   

 Rsyslog

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Steps

1. First you want to make sure rsyslog is installed, I also recommend going ahead and making sure its enabled to start automatically in case of server reboots

   Code Block
   language bash title Install snmptrapd
   apt-get install rsyslog systemctl enable rsyslog

   
   

2. Copy the rsyslog.conf file from nmis9/conf-default/rsyslog and replace the current rsyslog file.

   
   

   Code Block
   language bash title rsyslog
   #make a backup of the orginal cp /etc/rsyslog.conf /etc/rsyslog.conf.bak cp /usr/local/nmis9/conf-default/rsyslogd/rsyslog.conf /etc/rsyslog.conf

   
   

3. Now we will edit rsyslog to add in our snmptrap processing

   Code Block
   language bash title rsyslog.conf edit
   vi /etc/rsyslog.conf

   
   

   Code Block
   language text title rsyslog text add
   # Go to the end of the file and add: local2.* /usr/local/nmis9/logs/snmptrap.log

   
   

4. Reload and restart Daemon

   Code Block
   language bash title reload daemons rsyslog
   systemctl daemon-reload systemctl restart rsyslog # Always a good idea to check status systemctl status rsyslog

   
   

5. Time to test! To verify operation you can send a test trap either locally or from another Linux server, this example sends an Opmantek event trap.

   Code Block
   language bash title test trap
   sudo snmptrap -v 2c -c public 127.0.0.1 80000 1.3.6.1.4.1.4818 1.3.6.1.4.1.4818.1 s Event

   The trap will appear in either /usr/local/nmis9/logs/snmptrap.log

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If you are receiving SNMP traps from devices which are just numbers, then you will need to add the MIBS so that the SNMP trap daemon can decode them them for you.  First you need to identify the required MIB files and any dependant MIB files and then copy those files to the directory /usr/local/nmis9/mibs/traps and restart the SNMP trap daemon.

You can test the decoding using the snmptranslate command, which was described in a previous section.

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