Welcome into Protocol Deep Dive - SNMP.
My name is Greg Dickinson, and in this module,
we're going to give a brief overview of the SNMP protocol.
Specifically, we're going to talk about the different versions of SNMP.
There are three of them, and while they work very closely to the same,
there are some significant differences between the
three that you need to be aware of.
We'll talk about the data format,
more specifically what the packets look like when they're on the wire.
We'll talk about SNMP Gets versus Puts,
and talk about community strings and how you should never
ever let them out of your organization.
We'll talk about read-only community strings and read-write community strings.
And we'll talk about the difference between SNMP traps versus SNMP polling.
And finally,
we'll open up Wireshark and take a look at the packet
structure of SNMP network transactions.
So what is SNMP at a high-level?
SNMP allows a network management system,
which is quite simply a piece of software running on a server some place,
to collect data on a managed device and modify device parameters,
again, that's the read-only versus the read-write.
It uses a management information base, or a MIB,
to determine what parameters to gather.
Now I've just thrown a lot of terms at you there in a very
short period of time so let's talk about some of the terms
that we just talked about.
Managed devices, that a router, a server, refrigerator, a fish tank.
With the Internet of Things there is a great number of a devices that are
SNMP manageable that you wouldn't think of historically.
Not so much in the consumer space, but in the business space,
the corporate space,
you'll have SNMP management and monitoring of things like walk-in coolers,
HVAC systems, weather monitoring systems,
etc, basically a managed device in SNMP is anything that speaks SNMP.
The protocol has been around for quite a while as you'll see when we
talk about the individual protocols themselves.
And so, there are a lot of devices out there that speak SNMP.
The next is an SNMP agent, which runs on a managed device.
It's basically a small piece of software that talks
SNMP on Windows and Linux boxes.
It is a service that you install on industrial equipment,
it's probably an add-in board that runs a small SOC system like a
raspberry pie to talk to the system on the back-end and translate that
into SNMP data for a computer system to collect.
Next is a network management station,
which is quite simply the device that gathers all of this SNMP
data and collects it and displays it so that you can look at it
and make business decisions on it.
We'll install a network management station in the very end of this course,
but quite simply in most installations,
if you don't have some type of network management station,
you're not going to be able to make good sense out
of the SNMP data you're getting.
And finally, as a management information base,
that basically translates the raw SNMP data or the object IDs into
something that the management station can understand.
Now there are several industry standard management information bases,
but if you're going to get detailed information out of a
vendor-specific piece of hardware,
you're almost certainly going to have to install a
separate management information base,
and we'll go over MIBs when we install the network
management station at the end of the course.
If it sounds like a lot, don't worry,
SNMP at its very basis is a pretty simply protocol to
understand and get your arms around and we'll go over it throughout the rest of this course.