And finally we land over on our Windows server.
Now this is sort of an isolated Windows server.
It's not hooked up to my viral environment,
but we've proven that DHCP actually works as we expect it to,
and this is just how to configure DHCPv4 on a Windows infrastructure.
And so while we will be setting up actual DHCP scopes,
they won't be valid for the subnet that I have out there simply because
I like having a functioning network and don't like them calling me at
all hours of the night telling me that I've managed to their network by
configuring a rogue DHCP server.
So we're just going to make a wild, off the wall subnet for this network anyway.
So you'll notice that under IPv4 we have nothing under here,
no scopes, if we click on Server Options we have no server options,
no policies, or filters, there's nothing.
This is a completely brand new installation.
With the Windows DHCP server you have the concept of server
options and you have per scope options.
And again, these are the DHCP options that we talked about earlier in the module.
So if we wanted to set a server-wide option,
for example, all of the scopes that we have on this server,
we want to have the domain name of globomantics.
local.
So we find the DNS Domain Name option, which is option 15,
put in the string value globomantics.
local, we apply that,
and now this option applies by default to any scope
that we set up on this DHCP server.
So, if you have options that will be set the same for all of your branches,
say you have the same set of DNS servers,
say you have the same domain name,
which you almost certainly will except under some
unusual circumstances shall we say,
I would recommend setting them up here in the Server Options.
You can always override them on a per-scope basis when you configure that scope.
Speaking of configuring the scope, let's do exactly that.
So we'll right-click IPv4, and we'll say New Scope.
First thing we have to do is give it a name and a description.
We'll say Test Scope, Description of Test Scope.
Go ahead and hit Next,
and much like the Cisco configuration we're prompted for the
range of IP addresses that will be given out.
Now there's two schools of thought on how to set this up.
One is that you set up the entire subnet that matches your routing tables,
so if you're using /24 subnets then you set up the entire /24 subnet here in
the IP address range and then you use exclusions to block out the addresses
that you don't want to actually lease to clients.
Another school of thought is, you carve out just the 50,
or 75, or 100 addresses that you're putting out at that branch,
and that's the range that you put here in the Start IP address and
End IP address fields when you set up the scope.
Whichever way you go,
make sure you're consistent and just remember you can't
change this later on very easily.
I tend toward the first school of thought,
I'll match my routing table exactly that way,
if I have to expand the scope later on I can simply pair
down my exclusions and not necessarily have to re-set up
the entire scope from scratch.
In this case, I'll give the IP scope of 172.
16.
15.
1 to 172.
16.
15.
254.
In this case, it defaults to a /16 subnet because that's the proper subnet, 401.
72.
16.
In this case, we'll up this to a /24.
This is the actual subnet mask that's distributed to the client
that is irrespective of the Start IP address and End IP address
range that you specify up here.
So if I had gone in here and said 1 to 128,
I'm obviously only distributing the first half a class C network,
or technically to 127,
but my subnet mask link would still need to be a /24 if
that's what's in my routing table.
Go ahead and hit Next.
This is where you can set the exclusions and the delay if you have
multiple DHCP servers that will be servicing this particular subnet
that gives you a bit of redundancy.
In this case, I will exclude 1 through 100 just like on my other demonstration,
172.
16.
15.
100, add that.
You can have multiple exclusion ranges if you want to.
So let's say you block off everything above 225,
you could add that in here as well.
We will not enter a subnet delay.
Next is the Lease Duration.
Windows servers, at least on 2012,
I haven't set it up on 2016 yet I'll be honest,
defaults to 8 days.
In my opinion, that's probably good if this is a fairly static network, i.
e.
you have workstations out at a branch that hardly ever change,
no one brings laptops there,
or you don't otherwise have a lot of churn in your IP addresses there.
A lot of places will set that to be much lower.
Again,
my defaults are generally 8 hours because that's generally long enough that you
won't have an outage unless you have an extended downtime,
but it's not so long that you run the risk of leasing out addresses
that you then cannot release for another 6 days just because someone
wandered in with their laptop for a day.
Again,
there's pros and cons to having a long lease time versus a short lease time.
Again, if you have a really short lease time and your DHCP server is offline,
whenever the clients try to reapply for their IP
address or release their IP address,
then the clients will not be able to actually get an IP
address and you'll have an outage at your location that
this DHCP server is servicing.
Go ahead and hit Next, and we're prompted to configure DHCP options,
so we'll go ahead and look at them.
Again, the Default Gateway we could set that up at the server level,
but for every subnet it's probably going to be different.
In this case, 172.
16.
15.
254.
It gives you the parent domain.
Again, it defaults to that because that's what's in DNS.
You can override that if you want.
In this case, we actually will, globomantics.
local.
It defaults to the registered DNS servers in your Active Directory
if you're running as Active Directory integrated,
which come on, it's 2017,
who's not running a Windows network that has Active Directory?
Or rather I should say, if you're running a Windows network,
you're almost certainly using Active Directory.
So we'll go ahead and hit Next.
WINS Servers if you have them defined, this is where you'd set them.
And yes, I want to activate the scope now.
So now we see the Scope right here, and there's the Address Pool.
We can look at the Address Pool, it starts with 1 to 254,
there's the exclusions, there's the leases.
We have no leases, and we're not going to have any leases because again,
I like having a functioning network.
You can set reservations,
which is that automatic type of address assignment that we
discussed earlier in the module where a device has leased
an IP address permanently.
We can modify all the scope options here.
Again, there's that DNS domain name that came from the server itself,
but again, if we go here to Configure Options,
we could go down to any of the options that we wish to distribute to
our clients and modify them on a per-scope basis.
Now you'll notice that not all the options are in here.
I scrolled down to the bottom of the list purposely
to show you that for example, option 150 is missing,
and you might ask yourself, well, how do you add this option?
Obviously for non-Microsoft DHCP clients and servers,
you're going to need special options.
Again, option 150 is a good example.
Not a lot of people know how to do this and so what you'll run across on a
lot of Cisco voice networks is that the Cisco router at the local site
hands out the addresses on the voice subnet,
and then the centralized Windows DHCP server hands out the IP
addresses for the Windows workstations.
And me,
I don't like that because again that's spreading your
management across all of your branches.
So the way you add these options in, for example,
is you go up here to IPv4 because we're going to add an IPv4 option,
where I click this guy and you say Set Predefined Options,
and you hit the Add button here.
At what point you can add the Name, in this case we'll say TFTP Server.
The Data type is going to be an IP Address,
and we'll say it's an array just so you can have more than one IP address,
Code is 150, and Description is TFTP Server.
Again, the Description and the Name don't have to match.
So now we have option 150, we could set default options for them if we wanted to,
but we'll go ahead and hit OK,
and now if we go back to the Scope Options and do Configure Options,
if we scroll down to the bottom here,
we now have TFTP Server and we can add the IP addresses here.
And that's pretty much it.
That gets us configured for DHCPv4 on Cisco and Windows, and that closes out the module.