Simple Network Management Protocol (SNMP) is an Internet-standard
protocol for managing devices on IP networks. Many kinds of devices
support SNMP, including routers, switches, servers, workstations,
printers, modem racks, and uninterruptible power supplies (UPSs). The
ways you can use SNMP range from the mundane to the exotic:
it's fairly simple to use SNMP to monitor the health of your
routers, servers, and other pieces of network hardware, but you can
also use it to control your network devices and even send pages or
take other automatic action if problems arise. The information you
can monitor ranges from relatively simple and standardized items,
like the amount of traffic flowing into or out of an interface, to
more esoteric hardware- and vendor-specific items, like the air
temperature inside a router.
Given that there are already a number of books about SNMP in print,
why write another one? Although there are many books on SNMP,
there's a lack of books aimed at the practicing network or
system administrator. Many books cover how to implement SNMP or
discuss the protocol at a fairly abstract level, but none really
answers the network administrator's most basic questions: How
can I best put SNMP to work on my network? How can I make managing my
We provide a brief overview of the SNMP protocol in Chapter 2, "A Closer Look at SNMP" then spend a few chapters discussing issues
such as hardware requirements and the sorts of tools that are
available for use with SNMP. However, the bulk of this book is
devoted to discussing, with real examples, how to use SNMP for system
and network administration tasks.
Most newcomers to SNMP ask some or all of the following questions:
This book answers all these questions and more. Our goal is to
demystify SNMP and make it more accessible to a wider range of users.
- What exactly is SNMP?
- How can I, as a system or network administrator, benefit from SNMP?
- What is a MIB?
What is an OID?
What is a community string?
What is a trap?
I've heard that SNMP is insecure. Is this true?
Do any of my devices support SNMP? If so, how can I tell if they are
- How do I go about gathering SNMP information from a device?
- I have a limited budget for purchasing network-management software.
What sort of free/open source software is available?
- Is there an SNMP Perl module that I can use to write cool scripts?
0.1. Audience for This Book
This book is intended for system and network administrators who could
benefit from using SNMP to manage their equipment but who have little
or no experience with SNMP or SNMP applications. In our experience
almost any network, no matter how small, can benefit from using SNMP.
If you're a Perl programmer, this book will give you some ideas
about how to write scripts that use SNMP to help manage your network.
If you're not a Perl user you can use many of the other tools
we present, ranging from Net-SNMP (an open source collection of
command-line tools) to Hewlett Packard's OpenView (a high-end,
high-priced network-management platform).
Copyright © 2002 O'Reilly & Associates. All rights reserved.