How to enable SNMP on Linux

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Debian

1. Installation

$ sudo apt-get update

$ sudo apt-get install snmpd

2. Configuration

With a text editor of your choice.

Edit the file: /etc/snmp/snmpd.conf  

Add the following line:
rocommunity public

Note: The default Ubuntu “snmpd” configuration specifically denies almost everything functional with this configuration (limiting access to just enough information to tell that the machine is a Linux one):

view systemonly included .1.3.6.1.2.1.1
view systemonly included .1.3.6.1.2.1.25.1
rocommunity public default -V systemonly

This configuration locks the machine down, which may be “safe” if it is on an insecure network with little SNMP administration knowledge available. However, if you are willing to monitor the performance of your machine with external systems, comment on them and replace the access with a secure mechanism (either with SNMP v3 or a different community string).

Comment the line:
#agentAddress udp:127.0.0.1:161

Uncomment the line: 
agentAddress udp:161,udp6:[::1]:161

Restart the snmpd service:

$ /etc/init.d/snmpd restart

Ubuntu

1. Installation

$ sudo apt-get update

$ sudo apt-get install snmpd

2. Configuration

Edit the file: /etc/snmp/snmpd.conf  with a text editor of your choice.

Add the following line:
rocommunity public

Note: The default Ubuntu “snmpd” configuration specifically denies almost everything functional with this configuration (limiting access to just enough information to tell that the machine is a Linux one):

view systemonly included .1.3.6.1.2.1.1
view systemonly included .1.3.6.1.2.1.25.1
rocommunity public default -V systemonly

This configuration locks the machine down, which may be “safe” if it is on an insecure network with little SNMP administration knowledge available. However, if you are willing to monitor the performance of your machine with external systems, comment on them and replace the access with a secure mechanism (either with SNMP v3 or a different community string).

Comment the line:
#agentAddress udp:127.0.0.1:161

Uncomment the line: 
agentAddress udp:161,udp6:[::1]:161

Restart the snmpd service:

$ /etc/init.d/snmpd restart

3. Allow SNMP ports in the Firewall

Execute the following commands to allow necessary ports:

$ ufw allow 161/udp

$ ufw allow 162/udp

CentOS

1. Installation

$ yum update

$ yum install net-snmp

2. Configuration

Edit the file: /etc/snmp/snmpd.conf 

Add the next line:
rocommunity public

Replace the line below:
view systemview included .1.3.6.1.2.1.25.1.1
With the following line:
view systemview included .1.3.

Restart the snmpd service:

$ /etc/init.d/snmpd restart

3. Allow SNMP ports in the Firewall

Execute the following commands to allow necessary ports:

$ firewall-cmd --zone=public --add-port=161/udp --permanent

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

$ firewall-cmd --reload

FreeBSD

1. Fetch Ports collection and install Installation

$ portsnap fetch

$ portsnap extract

$ cd /usr/ports/net-mgmt/net-snmp

$ make install clean

2. Configuration

Copy the following configuration file:
cp /usr/local/share/snmp/snmpd.conf.example /usr/local/etc/snmpd.conf

Add the next line:
rocommunity public

Comment the line:
#agentAddress udp:127.0.0.1:161

Uncomment the line:
agentAddress udp:161,udp6:[::1]:161

3. Allow SNMP ports in the Firewall

Edit the /etc/rc.conf file and add the following lines:

snmpd_enable=”YES”
snmpd_conffile=”/usr/local/etc/snmpd.conf”

Uncomment the line:
agentAddress udp:161,udp6:[::1]:161

4. Start the Service

$ service snmpd start

Edit the /etc/rc.conf file and add the following lines:

Red Hat Enterprise Linux (RHEL)

1. Installation

yum install net-snmp

2. Configuration

Edit the file: /etc/snmp/snmpd.conf 

Add the following lines:
rocommunity public
agentAddress udp:161,udp6:[::1]:161

Start the snmpd service:
systemctl enable snmpd && systemctl start snmpd

3. Allow SNMP ports in the Firewall

Execute the following commands to allow necessary ports:

firewall-cmd --zone=public --add-port=161/udp --permanent

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

firewall-cmd --reload

Edit the /etc/rc.conf file and add the following lines:

Mac OS- How to enable SNMP on Mac OS

1. Configuration

Edit the file: /etc/snmp/snmpd.conf 

Add the following line:
rocommunity public

Please comment on the post if you find any errors or code needing updating.