How SNMP Works - a quick guide

Summary

This video provides a concise introduction to SNMP (Simple Network Management Protocol), covering its basics to help you start monitoring devices. It explains key terms like OIDs (Object Identifiers) and MIBs (Management Information Bases), and how SNMP works in practice, including polling and notifying methods. The video also discusses the different SNMP versions, highlighting the security advantages of version 3 over versions 1 and 2c. By the end, you'll understand how to use SNMP for monitoring network devices such as switches, routers, and servers.

Takeaways

• 📘 SNMP stands for Simple Network Management Protocol, introduced in 1988.
• 🔍 SNMP is used to monitor and modify settings on network equipment like switches, routers, and other devices.
• 🔑 Key terms to know: OID (Object Identifier) and MIB (Management Information Base).
• 🌡️ OIDs are unique identifiers for specific parameters on devices, such as temperature sensors.
• 📜 MIBs are text files that translate numerical OIDs into understandable names.
• 🖥️ Standard OIDs and MIBs are often built into SNMP implementations for basic monitoring.
• 🔄 SNMP can be used in two ways: polling (querying devices) and notifying (devices sending alerts).
• 🔐 There are three versions of SNMP: v1, v2c, and v3, with v3 being the most secure.
• 🛡️ Version 3 enhances security by requiring usernames, passwords, and offering encryption.
• ⚙️ Best practice is to use SNMP v3 whenever possible, although v2c is still commonly used.

Q & A

What does SNMP stand for?

SNMP stands for Simple Network Management Protocol.

Since when has SNMP been in use?

SNMP has been in use since 1988.

What was the initial purpose of SNMP?

SNMP was initially developed to allow administrators to monitor networking equipment's current state and remotely modify settings and configurations on the equipment.

What are the two key terms introduced in the script related to SNMP?

The two key terms introduced are OID (Object Identifier) and MIB (Management Information Base).

What is an OID in the context of SNMP?

An OID is a numerical identifier used to represent anything and everything on a device that can be monitored with SNMP.

What is a MIB and why is it used?

A MIB is a text file that allows us to translate numerical OIDs into more understandable names, making it easier to identify what is being monitored.

Why are MIBs considered helpful in SNMP monitoring?

MIBs are helpful because they simplify the process of identifying and monitoring various parameters on a device by translating numerical OIDs into more comprehensible names.

What are the two primary methods by which SNMP can be used to monitor devices?

The two primary methods are polling, where the network monitoring system requests information from the device, and notifying, where the device sends information to the monitoring system.

What is the main difference between SNMP versions 1 and 2c and version 3 in terms of security?

Version 3 is more secure than versions 1 and 2c because it requires a username and password and offers encryption, whereas versions 1 and 2c only require a community string and do not offer encryption.

Why might some administrators still use SNMP version 2c despite the availability of version 3?

Some administrators might still use SNMP version 2c because not all devices and operating systems support version 3, and it is often still considered sufficient for their needs.

What is the recommended best practice regarding the use of SNMP versions?

The best practice is to use SNMP version 3 whenever possible due to its enhanced security features.

Where can one find information about OIDs and MIBs for specific devices?

Information about OIDs and MIBs for specific devices can typically be found in the product manuals from the manufacturer, which are often available online.

Outlines

00:00

🔍 Introduction to SNMP Explainer

This introductory paragraph sets the stage for an SNMP explainer video. The speaker promises to teach the basics of SNMP for device monitoring, emphasizing simplicity and avoiding unnecessary complexity. SNMP, or Simple Network Management Protocol, has been in use since 1988 and is designed for monitoring and remotely modifying network equipment. The script mentions that SNMP is not limited to switches and routers but can also be used for a variety of devices, including Windows and Linux machines, printers, and UPS systems. Two key terms, OID (Object Identifier) and MIB (Management Information Base), are introduced as essential concepts for understanding SNMP.

05:02

📚 Understanding SNMP Operations and Security

The second paragraph delves into the practical use of SNMP, explaining how it operates in daily practice through polling and notifications. Polling involves the monitoring system requesting information from a device, while notifications allow devices to send unsolicited messages about certain OIDs. The paragraph also discusses the evolution of SNMP versions, highlighting the security improvements in SNMP version 3, which includes authentication and encryption not present in versions 1 and 2c. The speaker advises using SNMP version 3 whenever possible for enhanced security, but acknowledges that not all devices support it. The video concludes by encouraging viewers to start monitoring with SNMP and provides a link to download Nagios XI for monitoring purposes.

Keywords

💡SNMP

SNMP stands for Simple Network Management Protocol. It was developed in 1988 to allow administrators to monitor and modify network devices' states and configurations. The video explains how SNMP is essential for monitoring devices like switches, routers, and even printers.

💡OID

OID stands for Object Identifier. It is a series of numbers separated by dots that uniquely identifies a specific parameter that can be monitored on a device. For example, the temperature sensor on a network device has an OID, making it possible to monitor its value through SNMP.

💡MIB

MIB stands for Management Information Base. It is a text file that translates numerical OIDs into human-readable names, making it easier to understand what is being monitored. For example, instead of using the numerical OID for a temperature sensor, a MIB allows the use of a word-based identifier.

💡Nagios

Nagios is a network monitoring system that uses SNMP to monitor various devices. It can ask devices for information on specific OIDs and interpret the responses. The video mentions Nagios XI as an example of a tool that can utilize SNMP for device monitoring.

💡Polling

Polling is one method of using SNMP, where the network monitoring system connects to the device on port 161 and requests information on specific OIDs. The device then responds with the requested information. This method is essential for regular and automated device monitoring.

💡Notifying

Notifying is another method of using SNMP, where the device sends a message about an OID to the network monitoring system's port 162. These messages can be called traps, notifications, or informs, and they alert the monitoring system to specific events or changes in the device's status.

💡Community String

A Community String is a password used in SNMP versions 1 and 2c to grant access to network devices. It is a simple form of authentication. The video explains that version 3 replaces the community string with a username and password for better security.

💡Version 3

Version 3 of SNMP is the most secure version, offering both authentication and encryption. It requires a username and password, unlike versions 1 and 2c, which only use a community string. The video emphasizes using version 3 whenever possible due to its enhanced security features.

💡Traps

Traps are unsolicited notifications sent from a device to a network monitoring system, indicating that a specific event has occurred. This is part of the notifying method in SNMP. Traps help in alerting administrators about issues without needing constant polling.

💡Encryption

Encryption in SNMP version 3 protects data from being intercepted and read by unauthorized parties. The video highlights that versions 1 and 2c do not offer encryption, making them less secure. Encryption is crucial for preventing attackers from manipulating device settings.

Highlights

Introduction to SNMP (Simple Network Management Protocol) and its purpose.

SNMP has been around since 1988 and is used to monitor and manage network devices.

SNMP can monitor a variety of devices including switches, routers, Windows and Linux machines, printers, and UPS systems.

Key terms: OID (Object Identifier) and MIB (Management Information Base).

OID is like an IP address for values to monitor, such as device temperature.

MIB is a text file that translates numerical OIDs into readable text-based OIDs.

Standard OIDs and MIBs are incorporated into most SNMP implementations by default.

Basic device information like uptime can be monitored without needing specific OIDs or MIBs.

For non-standard monitoring, product manuals from manufacturers often provide necessary OIDs and MIBs.

Two ways to use SNMP: polling and notifying.

Polling involves the network monitoring system requesting information from a device.

Notifying involves the device sending information to the network monitoring system.

Three versions of SNMP: version 1, version 2c, and version 3, with version 3 being the most secure.

Version 3 requires a username and password and offers encryption.

Despite its security advantages, not all devices support SNMP version 3.

It is best practice to use SNMP version 3 whenever possible.

Summary: Understanding OIDs, MIBs, polling, traps, and SNMP versions prepares you to start monitoring with SNMP.

Download Nagios XI for practical SNMP monitoring.

Transcripts

[Music]

hey everybody welcome to this SNMP

explainer in just a couple of minutes

I'm gonna teach you enough about SNMP to

be able to start monitoring devices

while SNMP is a little complex there's a

lot you don't need to know just to start

monitoring so we're gonna focus on the

absolute basics here and I promise I

won't get you lost in unnecessary

details how are we gonna do that

well we're gonna talk about some basic

background information we're gonna talk

about two key terms you need to know

we're gonna talk about why switches and

routers are simple to monitor we're

gonna talk about how SNMP works on a

practical level and we're gonna talk

about the different versions of SNMP are

you ready let's get started

SNMP stands for simple network

management protocol it's been around

since 1988 so it's pretty well used SNMP

was developed to allow administrators to

both monitor networking equipments

current state and also remotely modify

settings and configurations on the

equipment while SNMP was initially

developed for switchers and routers it

has since been extended to a wide array

of other devices such as Windows and

Linux machines printers and

uninterruptible power supplies among

many many other things there are two key

terms you need to know ID and mim o it

is short for object identifier think of

it like this anything and everything on

a device that can't be monitored with

SNMP has annoyed for example say I want

to monitor the temperature on a network

attached storage device we have here

Nagios the oil for the temperature

sensor on the device is a bunch of

numbers separated by dots that number

might look confusing but all you really

have to know is each thing we can

monitor like device temperature has

annoyed you might think of annoyed as

something similar to an IP address for a

value we use an application like Nagios

X I to ask the device what the value of

any particular I'd have to be mint is

short for management information base

that sounds a lot more complicated than

it actually is am it is a text file that

allows us to translate numerical oils

into

bass toys so instead of using the

numerical oi for the temperature sensor

in our example we can use this word

based oil which makes it a lot easier to

understand what we're monitoring now

technically you don't have to use MIBs

at all you could always use only

numerical hoids but MIBs can make your

life a lot easier there are a number of

standard Lloyd's and MIBs that are

incorporated into most SNMP

implementations by default for example

on almost any system out there you

should be able to ask the uptime of a

device with the oeid cysts uptime zero

this is great because when you go to do

basic switch or router monitoring in

Nagios x.i you don't need to know a

single weight or find any mips because

those are already built in you really

only need to figure out ways and MIPS

when you have a non-standard

to monitor like the temperature sensor

on a network attached storage device

like we just talked about a minute ago

how do you find out what the oeid are

and where do you find MIPS the best

place to start on both of those

questions will be the product manuals

from the manufacturer of the device many

times these documents are available

online and a simple search will get you

the information you need so here is how

SNMP gets used in day-to-day practice

you have a network monitoring system

like Nagios this is what monitors the

things you want to monitor and then you

have the things you want to monitor like

switches and routers and servers and

uninterruptible power supplies there are

two ways to use SNMP the first way is

called polling with polling the network

monitoring system connects to the

monitored device on port 161 and tells

the device which ID it wants information

on the device then responds with the

information to the network monitoring

systems port 161 in the second way we do

what's called notifying with notifying

the device simply sends a message about

a noid to the network monitoring systems

port 162 these messages are variously

called either traps notifications or

informs there are three versions of the

SNMP protocol version 1 version 2c and

version 3 the biggest difference for our

purposes is that version 3 is more

secure than versions 1

to see in two ways first four versions

one and two see you don't even have to

supply a username all you need is a

special password called the community

string version three gets rid of the

community string and makes admins

specify a username and a password

second versions one and two C don't

offer encryption but version 3 does keep

in mind that SNMP can be used to change

device settings so if an attacker were

able to intercept and read your

unencrypted v1 or v2 C SNMP packets the

attacker could take control of the

device you might find out there that

SNMP version 2 C is still pretty

commonly used why wouldn't everyone

always use version 3 well quite simply

for a number of reasons not all devices

and operating systems support version 3

it is best practice however to use

version 3 whenever possible you now know

enough to be dangerous you know about

Lloyd's and MIPS you know about the two

ways to use that cmp to monitor that

would be polling and traps

you know switches and routers are easy

to monitor and you know about SNMP

versions you know enough to get out

there and start monitoring with SNMP

thanks for watching download Nagios exei

from the link in the description below

and you'll be monitoring in no time