Install SNMP Service on RHEL or CentOS

In this article we are going to learn how to install and start SNMP service in RHEL/CentOS.

We need to have net-snmp rpm package installed on the servers , generally it would come with repository.

1. Install net-snmp with yum:

#yum install net-snmp

[root@umserv]# yum install net-snmp
Loaded plugins: dellsysid, fastestmirror
Loading mirror speeds from cached hostfile
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Dependencies Resolved

========================================================================================================================================================================
Package Arch Version Repository Size
========================================================================================================================================================================
Installing:
net-snmp x86_64 1:5.3.2.2-22.el5_10.1 updates 708 k
Installing for dependencies:
lm_sensors x86_64 2.10.7-9.el5 base 525 k
Updating for dependencies:
net-snmp-libs i386 1:5.3.2.2-22.el5_10.1 updates 1.3 M
net-snmp-libs x86_64 1:5.3.2.2-22.el5_10.1 updates 1.3 M

Transaction Summary
========================================================================================================================================================================
Install 2 Package(s)
Update 2 Package(s)
Remove 0 Package(s)

Total download size: 3.8 M
Is this ok [y/N]: y
Downloading Packages:
(1/4): lm_sensors-2.10.7-9.el5.x86_64.rpm | 525 kB 00:01
(2/4): net-snmp-5.3.2.2-22.el5_10.1.x86_64.rpm | 708 kB 00:02
(3/4): net-snmp-libs-5.3.2.2-22.el5_10.1.i386.rpm | 1.3 MB 00:04
(4/4): net-snmp-libs-5.3.2.2-22.el5_10.1.x86_64.rpm | 1.3 MB 00:03
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Total 168 kB/s | 3.8 MB 00:23
Running rpm_check_debug
Running Transaction Test

Finished Transaction Test
Transaction Test Succeeded
Running Transaction
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Installed:
net-snmp.x86_64 1:5.3.2.2-22.el5_10.1

Dependency Installed:
lm_sensors.x86_64 0:2.10.7-9.el5

Dependency Updated:
net-snmp-libs.i386 1:5.3.2.2-22.el5_10.1 net-snmp-libs.x86_64 1:5.3.2.2-22.el5_10.1

Complete!
[root@umserv]#

2. Simple SNMP configuration:

mv /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf.old

Add below configuration to /etc/snmp/snmpd.conf

rocommunity public xxx.xxx.xxx.xxx
rocommunity public 127.0.0.1
syslocation "HYD, UM DataCenter"
syscontact surya@unixmantra.com

Replace xxx.xxx.xxx.xxx with the IP address of the server that you want to allow SNMP lookups from:
rocommunity public xxx.xxx.xxx.xxx

3. Start the SNMP service, and set it to auto-start on reboot:

/etc/init.d/snmpd start
chkconfig snmpd on

Note:If you have a firewall configured, ensure that you have UDP port 161 open to your SNMP lookup server.

4) Validation:

On your SNMP lookup server, you can do the following to perform a quick SNMP test to ensure that it’s working.

snmpwalk -v 2c -c public xxx.xxx.xxx.xxx or snmpwalk -v 1 -c public -O e 127.0.0.1
[root@umserv ~]# snmpwalk -v 1 -c public -O e 127.0.0.1
SNMPv2-MIB::sysDescr.0 = STRING: Linux umserv 2.6.18-92.1.17.el5 #1 SMP Mon Jul 14 06:07:13 IST 2014 i686
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (16748) 0:02:47.48
SNMPv2-MIB::sysContact.0 = STRING: surya@unixmantra.com
SNMPv2-MIB::sysName.0 = STRING: umserv
SNMPv2-MIB::sysLocation.0 = STRING: "HYD, UM DataCenter"
SNMPv2-MIB::sysORLastChange.0 = Timeticks: (1) 0:00:00.01
...
...

Yes, it is working