Debian / Ubuntu Linux: Install and Configure snmpd Service

 

 

Debian / Ubuntu Linux: Install and Configure snmpd Service

 

SNMP (Simple Network Management Protocol) is a protocol used for network management. How do I install SNMP server under Debian or Ubuntu Linux to configure various monitoring service?

 

The NET-SNMP project provides various SNMP tools: an extensible agent, an SNMP library, tools for requesting or setting information from SNMP agents, tools for generating and handling SNMP traps, a version of the netstat command which uses SNMP, and a Tk/Perl mib browser. The snmpd package contains the snmpd and snmptrapd daemons, documentation, etc.

Install snmpd

 

Type the following command as root, enter:

# apt-get update && apt-get install snmpd

Snmpd Configuration Files

 

The default configuration for snmpd is rather paranoid for security reasons. Edit /etc/snmp/snmpd.conf or run snmpconf to allow greater access. You can individually control whether or not snmpd and snmpdtrap are run by editing /etc/default/snmpd.

Configure SNMPD

 

Edit /etc/snmp/snmpd.conf, enter:

# vi /etc/snmp/snmpd.conf

 

Edit or update file as follows:

smuxsocket 127.0.0.1

rocommunity setMeHere

com2sec local localhost public

group MyRWGroup v1 local

group MyRWGroup v2c local

group MyRWGroup usm local

view all included .1 80

access MyRWGroup "" any noauth exact all all none

com2sec notConfigUser default mrtg

group notConfigGroup v1 notConfigUser

group notConfigGroup v2c notConfigUser

view systemview included .1.3.6.1.2.1.1

view systemview included .1.3.6.1.2.1.25.1.1

view systemview included .1 80

access notConfigGroup "" any noauth exact systemview none none

syslocation Mumbai, IN (VSNL LB3)

syscontact Vivek Gite <alert.client22@route.nixcraft.in>

 

See snmpd.conf(5) man page for details. Edit /etc/default/snmpd, enter:

# /etc/default/snmpd

 

Update it as follows:

# This file controls the activity of snmpd and snmptrapd

# MIB directories. /usr/share/snmp/mibs is the default, but

# including it here avoids some strange problems.

export MIBDIRS=/usr/share/snmp/mibs

# snmpd control (yes means start daemon).

SNMPDRUN=yes

# snmpd options (use syslog, close stdin/out/err).

# replace 204.x.y.z with your public IP

SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/snmpd.pid 127.0.0.1 204.x.y.z'

# snmptrapd control (yes means start daemon). As of net-snmp version

# 5.0, master agentx support must be enabled in snmpd before snmptrapd

# can be run. See snmpd.conf(5) for how to do this.

TRAPDRUN=no

# snmptrapd options (use syslog).

TRAPDOPTS='-Lsd -p /var/run/snmptrapd.pid'

# create symlink on Debian legacy location to official RFC path

SNMPDCOMPAT=yes

Restart Snmpd Service

 

Type the following command:

# /etc/init.d/snmpd restart

 

Sample outputs:

Restarting network management services: snmpd.

Firewall Configuration

 

Here is a sample firewall config file:

#!/bin/sh

# set shell vars

PUB_IF="eth0"

SNMPD_CLIENT="85.x.y.z"

SNMPD_SERVER="203.a.b.c"

IPT="/sbin/iptables"

LO_IF="lo0"

# DROP and close everything all incoming traffic

$IPT -P INPUT DROP

$IPT -P OUTPUT DROP

$IPT -P FORWARD DROP

# Allow Full Outgoing connection but no incoming stuff by default

$IPT -A INPUT -i ${PUB_IF} -m state --state ESTABLISHED,RELATED -j ACCEPT

$IPT -A OUTPUT -o ${PUB_IF} -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT

# Unlimited lo access

$IPT -A INPUT -i ${LO_IF} -j ACCEPT

$IPT -A OUTPUT -o ${LO_IF} -j ACCEPT

### Open port 161 ###

$IPT -A INPUT -i ${PUB_IF} -s ${SNMPD_CLIENT} -d ${SNMPD_SERVER} -p udp --dport 161 -j ACCEPT

### rest of iptables goes here ###

Test It

 

From local or remote system type the following command:

# snmpwalk -v 1 -c mrtg 204.x.y.z IP-MIB::ipAdEntIfIndex

 

Sample outputs:

IP-MIB::ipAdEntIfIndex.10.20.110.2 = INTEGER: 2

IP-MIB::ipAdEntIfIndex.127.0.0.1 = INTEGER: 1

IP-MIB::ipAdEntIfIndex.204.xx.yy.zz = INTEGER: 3