1. Introduction

SNMP4Nagios is a package of Nagios plugins which use SNMP to query hosts. While some of the plugins use standard MIBs, most are designed for vendor specific agents.

Unlike other Nagios plugins, they are able to scan hosts for objects which can be monitored. They also can keep performance logs and draw plots of these using Tobias Oetiker's RRDTool.

While not strictly necessary, SNMP4Nagios plugins should be most useful when embedded into site specific scripts to handle scanning and plotting.

1.1. Typographical conventions

Throughout this document those typographical conventions are used to mark various types of text.

1.2. System Requirements

The plugins use libraries from the following software packages:

• Net-SNMP, see http://www.net-snmp.org/
  Note: Net-SNMP itself depends on other libraries. Currently there is no way of automatically testing if the development files of those libraries are actually installed. See Section 3.2.1. for further information about known problems.
• RRDTool, see http://oss.oetiker.ch/rrdtool/.
  Optional.

And obviously they are designed to be used with Nagios, see http://www.nagios.org/.

1.2.1. Versions of RRDTool

Systematic testing with various versions of RRDTool revealed that SNMP4Nagios is very picky about the librrd it uses. It was developed using 1.0.49 which is incidently the version which works best.

Under circumstances currently unknown version 1.0.50 builds shared objects (library files) which do not have a “.so” extension. This is not detected during configuration but building SNMP4Nagios fails. To work around this issue change into RRDTool's library directory and create symbolic links with the correct names:

root@host# ln -s librrd.0.0.0 librrd.so
root@host# ln -s librrd.0.0.0 librrd.so.0
root@host# ln -s librrd.0.0.0 librrd.so.0.0.0

RRDTool version 1.2.12 has a problem with Stacks upon Lines. These plugins may fail to produce usable plots due to this issue:

• check_cisco_mem
• check_mail_server
• check_ucd_snmp_cpu
• check_ups_battery
• check_winf_cpuusage

RRDTool version 1.2.16 changed the way escape sequences are handled¹ … and this breaks the SNMP4Nagios plugins.

RRDTool version 1.2.17 fixes that bug but has a problem selecting the right archive.²

Additionally libart (which is used by RRDTool 1.2.x) “is quite picky about the data it gets for drawing”³. This may result in “*** attempt to put segment in horiz list twice” messages.

For the time being RRDTool 1.0.49 is still strongly recommended.

1.3. Other Requirements

Before using the plugins, ensure that you meet the following prerequisites:

• Basic knowledge of SNMP
• Working knowledge of Nagios configuration

1.4. Licensing

SNMP4Nagios (except this document) is licensed under the terms of the GNU General Public License Version 2 or (at your option) any later version, as published by the Free Software Foundation.

Read appendix C. or the online version of the license at http://www.gnu.org/copyleft/gpl.html for more details.

This document is licensed under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in appendix B..

SNMP4Nagios is provided as is with no warranty of any kind; without even the warranty of design, merchantability, or fitness for a particular purpose.

1.5. Downloading the Latest Version

The latest version of SNMP4Nagios is available at:
http://sourceforge.net/project/showfiles.php?group_id=156977

You may find further information on SNMP4Nagios on the project's homepage:
http://snmp4nagios.sourceforge.net/

¹https://lists.oetiker.ch/pipermail/rrd-announce/2007-January/000091.html

²https://lists.oetiker.ch/pipermail/rrd-announce/2007-January/000001.html

³https://lists.oetiker.ch/pipermail/rrd-users/2006-February/010920.html