- [Instructor] Let's take a look at how we can
configure SNMPv2 here.
You can see our topology here at the top,
and what we want to do is to configure SNMP monitoring
only from the two SNMP agent devices,
R2 and R3 in this case at 10.1.1.5 and 20.1.1.5.
So first thing let's create a standard IP access list
for those devices.
This is going to make sure that we're only permitting
those two particular SNMP agents to communicate.
So we'll go under global configuration mode
and we can say access-list.
I'll call that list number one, I'll use a permit statement
and I want to permit 10.1.1.5 first of all,
and I will create another one of those statements
for 20.1.1.5 so I'll do both of those.
This step is optional by the way
but it's a really good way to increase your
security posture when you're using SNMP.
So we're still under global configuration mode.
And the next thing we want to say is SNMP-server.
To enable SNMP on this router.
Now, if we look at our contextual help,
you can see the many many options that we have here,
since we're looking at SNMPv2 in this case,
remember that this particular version uses community strings
just like version one and near the top of this contextual
help output we do see the key word community,
so let me break out of this output and we can use
the keyword community and to contextual help again
is going to indicate that we can now set
the community string to whatever we'd like.
I'm just going to use a really simple one,
I'll use Cisco all lowercase.
That's not an ideal community string by the way,
but I just wanted to keep it really simple for this example.
If we look at contextual help again,
you can see that now we have a couple of relevant
options here that I want to point out.
We see ro and rw those are going to be Read-only access
for ro and rw will give full Read-write permission.
If we're using SNMPv1 which doesn't support the informed
command to make configuration changes,
we might choose ro for read-only or if we want to restrict
this particular SNMP manager for any reason,
we might also use that.
I'm going to choose the rw option here
and I'm going to give that both read and write access.
If we look at help, again it indicates
that we've narrowed down our remaining options.
Now we can call out our ACL number that we've created
that standard ACL for our two approved hosts
and that was ACL number one and after that we can hit Enter.
Next, let's use the command SNMP-server followed by
the keyword host and this command is going to let us
identify the IP address of the SNMP manager to which
those traps are going to be sent and you can see from
our topology that is 50.1.1.5.
If we look again at our contextual help,
I want to point out that if we're using SNMPv1
the only other things that we'd require
you can see at the top of the list,
the community string, you see that it's prompting for that,
that's one of our options.
So if we were using version one,
remember that's used for both version one and two
but with version one we could put in this community string
and we would complete this configuration.
Now since we're using version two we won't do that.
What I will choose is the informs key word.
Remember that version two added support for
the informed request type and that particular
option will require the SNMP manager to
acknowledge receipt of the trap messages by echoing
the request back to the agent.
So I'll use that key word and if I look at help again,
you can see that now we need to specify
the version that we're using,
so I can say version and we'll look at our help options.
Really simple one, two C or three so we can see
those options here we have v1, v2C or v3.
I'll use v2 so I'll use that two key word
because we're configuring SNMPv2c in this example,
if we leave this out completely,
then it's going to default to the regular SNMPv1 traps.
Now if we look at our help,
the only thing left is to configure our community string,
which will be Cisco and all lowercase.
If we use contextual help again, you can see
the many many different options here for
which traps we want to accept.
Now by default, all traps are going to be sent,
so if we want to narrow that down to anything specifically,
we can look through this list and we can do that here.
I'm going to leave this in place in my case,
I'm not going to identify any of these keywords,
so I'll leave the default in place to accept all trap
messages by just simply hitting Enter.
And that completes the configuration for SNMPv2,
it's really simple.
You would of course want to repeat these steps on
the other agent machines as well to make sure
the community strings matched for communication.
And you would want to do that on
the SNMP manager software as well.
Now, configuring an SNMP manager software
that's outside of the scope of this particular exam,
but you'll want to be aware that the software would
need to be configured with the same community string
as well in order to have successful communication.
So that's a look at how we can configure
SNMPv2c on a Cisco device.