FaceITNet: Configure DHCP server with IP filtering and Reservation on server 2016

Dynamic Host Configuration Protocol (DHCP) automatically provides TCP/IP configuration including IP address, subnet mask, DG, DNS server and other parameters. This lab provides the required knowledge to install and manage the DHCP Server

Install DHCP role

We can install DHCP server role through server manager then add roles or from the PowerShell, follow

All the instructions are in the figures below.

-First option from PowerShell

- Second from Server Manager

Go to server manager and add the role DHCP and continue the process as usual. This is just installing the service. Once the service is installed you need to configure the DHCP service.

Now the service has been installed successfully. We need to configure the DHCP service now.

DHCP Post Installation Configuration

DHCP must be authorized in Active Directory to lease IP addresses to DHCP clients, this process done by domain admin account.

Configuring DHCP

Create and configure new scope DHCP scope, is a valid range of IP addresses that DHCP server lease to clients, to add and configure scope options follow instructions as explained below. Run dhcpmgmt.msc to access DHCP wizard or go to DHCP and right click on DHCP Manager .

Right click on the IPv4 and select New Scope

You can remove an IP address or range of IP addresses from the pool of addresses that DHCP server leased, so you can assign it in static way

By default, DHCP leases set to 8 days, you can increase or decrease it according your requirement

· At day 0 it will request a new lease

· During normal operation, the client can use the address

· Halfway the lease time it will try to renew the lease so it can keep the same IP address.

· If renewing failed (DHCP server is offline for example), it will try to extend the current lease with any active DHCP Server.

Configure most common DHCP options, also you can do it later

Configure default gateway (DG) to obtain by DHCP.

Select DNS server to obtained by DHCP (in our scenario we have domain (DNS Server) named faceitnet.com.au) which have two DNS servers 192.168.20.3

If we have WINs Server, you can add it here.

DNS maps TCP/IP host names to IP addresses and WINS maps NetBIOS host names to IP addresses.

WINS is an essential part of the Microsoft networking topology. In the older days, you were required to run a WINS server in order to avoid name resolution problems within a Windows network.

Today, DNS has replaced WINS, since Microsoft made changes to NetBIOS, allowing it to use the TCP/IP stack to perform its job

Activate your scope with options we configured, or you can activate later

Your configuration successfully DONE, and DHCP ready to response to DHCP clients.

Now let’s go to DHCP client and test the DHCP configurations.

Test DHCP functionality from Windows Client (Windows 10)

1- DHCPDiscover, DHCP client send broadcast message to the network to detect the DHCP server.

2- DHCPOffer, DHCP server which receive the Discover message also send broadcast message to DHCP client that send the discover message to Offer TCP/IP configuration.

3- DHCPRequest, DHCP client broadcast request that contain accept for offered TCP/IP configuration.

4- DHCPACK, DHCP server replay broadcast with acknowledging client that now you have TCP/IP configuration with lease duration.

5- After 50% of lease time client request DHCP server unicast to renew its lease duration, if the sever are available, the server will response to the client with unicast DHCPAck and renew its lease time. If there is a network connectivity problem between DHCP Server and client, the DHCP client will try again to contact the DHCP server at 87.5% of lease time for renewal but at this point the process go broadcast starting from DHCPRequest. If still there are a network connectivity between DHCP server and its client the sever will lease the client configuration to another client

First thing first, you need to remove the DHCP option from VMWare NAT configuration. If you have this enabled then the client will have two DHCP services and we cannot see the expected outcome.

Go to Network Configuration and make sure you have removed the static IP address configuration and selected the Obtain IP address automatically

Now go to Network Connection again and right click. Go to Status and confirm the IPs are received from DHCP server

Now let’s go and explore the DHCP service.

DHCP Scope Options: Address leases

Address leases tab show you computers that obtained TCP/IP configuration from DHCP server, with information about lease expiration and clients MAC addresses

DHCP Exclusion

As we have mentioned earlier, we can exclude IP or rang from DHCP scope leases here is we can configure this option from this tab, also in this tab we will see DHCP scope rang, as explained in the figures below.

DHCP Reservation

You can reserve specific IP address to specific client by assign specific IP to client MAC address, it is useful when you are setting up network devices such as printers, network storage, or server.

First check the MAC address of the device you are going to reserve the IP Address. Note down the MAC and we will use this in the next step.

Go to DHCP Reservations

Now go to Desktop client and release and renew the IP to confirm the reservation is working.

Check the DHCP Address lease and see the different

You can also reserve the IP once the DHCP server leased by just right clicking on the IP address under Address Leases

DHCP Filter

You can force DHCP to only response to specific clients by adding MAC addresses to allow list filter, also, you can deny any DHCP client request from specific computers by adding MAC addresses to deny list filter.