Dynamic Host Configuration Protocol (DHCP) Server Administration

  Microsoft Windows Server 2016

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Disable VirtualBox DHCP

17: Lame

What is DHCP?

18: https://www.udemy.com/windows-server-2016/learn/v4/t/lecture/5814156?start=0

What-is-DHCP-Handout

What is DHCP

  • Dynamic Host Configuration Protocol
    • Windows Server Role
  • Allows automatic TCP/IP configuration
    • IP
    • Subnet
    • Gateway
  • IPs are ‘leased’
  • prevents mistakes

DHCP Types

  • DHCP Exclusion
    • Cannot issue
    • No expiration
  • DHCP Reservation
    • Reserved for other persons or computers
    • No expiration
  • Available
    • Leased – default 8 days.
    • May get same IP after expiration (extension)
    • or a new IP

Scope

  • Specify the range available
    • 192.168.1.100-200
    • Only 1 range per subnet!
  • Exclusions
    • 192.168.1.105-110
  • Reservations
    • Based on MAC addresses
    • 192.168.1.10 reserved for 1F-B8-DD-92-5A-5F
  • Private IP address – 169.254.x.x
    • No DHCP server found on network

DHCP Example

  • Workstation configured for DHCP is not plugged into the network.
    • Assigns itself 169.254.x.x address
  • Plugged into the switch
    • Sends a DHCP Discover Request to entire network.
  • DHCP server receive request and send an ‘Offer’
    • Offer includes all TCP/IP settings
      • IP
      • Subnet
      • DNS
      • Gateway
      • etc
  • Workstation sends DHCP Request
    • “I want to keep these settings”
  • Server replies with ‘Ack’ saying “Okay, they are yours”
  • DORA
    • Discover
    • Offer
    • Request
    • Acknowledgement

Why use Static IPs?

  • DNS Servers
    • You would need to continually update each server’s settings!
  • Domain Controllers
  • Printers / Scanners
  • Any server providing a service
  • DHCP Reservations same as static IP?
    • DHCP Server crashes
    • Workstations with Static IP would not lose connectivity
    • Workstations with Reservations will lose connectivity AFTER their lease expires

Adding the DHCP Server Role

19: https://www.udemy.com/windows-server-2016/learn/v4/t/lecture/5814154?start=0

Install the Role

  • Server Manager > Manage > Add roles and features
  • Click through to “Select server roles”
  • Select [X] DHCP Server
  • Click through [Install]
  • Notification Flag -> Complete DHCP configuration

Access the DHCP Server Role

  • Tools > DHCP

DHCP Scope and Exclustions

20: https://www.udemy.com/windows-server-2016/learn/v4/t/lecture/6054262?start=0

Scope

  • Each subnet can only have 1 scope with a continuous range of IP addresses
    • Example: 192.168.1.20 – 192.168.1.220
  • Tools > DHCP > server.domain.com > Right click IPv4 > New Scope …
    • Scope Name: Up to you….
      • Workstations
    • Description: Good idea to use the IP address/range
      • 172.16.0.10 – 250
    • [Next >]
  • IP Address Range
    • Start IP
    • End IP
    • Length & Subnet Mask
      • Automatically calculated based on the IP address.
      • I had to adjust mine because it automatically assumed my 172 address was a /16 🙁
    • [Next >]
  • Add Exclusions and Delay
    • Start and End IPs of a range of IPs to exclude.
      • You can add multiple exclusions to a range.
    • Delay setting was ignored and not discussed.
    • [Next >]
  • Lease Duration
    • How long to allow a device to keep the assigned IP
      • Default: 8 days
    • [Next >]
  • Configure DHCP Options
    • (*) Yes, I want to configure these options now
      • This allows the server to also send the Default Gateway IP and other important address to the clients to auto-configure
    • [Next >]
  • Router [Default Gateway]
    • Multiple IPs can be added..
    • 172.16.0.1
    • [Next >]
  • Domain Name and DNS Servers
    • Parent domain:
      • domain.com (auto populated)
    • IP Address
      • Also auto-populated with the IP of the Domain Controller
    • [Next >]
  • WINS Servers
    • Similar to DNS
    • Obsolete for the most part, so leave it blank
    • [Next >]
  • Activate Scope
    • Yes or No
      • (*) No
    • [Next >]
  • [Finish]

Enable the Scope from the DHCP Manager

If you see the following folder icon with a red down-facing arrow, the scope has not been enabled

  • Right click Scope > Activate
  • Address Pool
    • The full range of available addresses
    • Any Exclusions
  • Address Leases
    • All computers that have received an IP from the DHCP server
  • Reservations
    • All computers/devices that have a DHCP reservation
  • Scope Options
    • Display pre-configured details that are shared with any DHCP requesting devices
    • Router
    • DNS Servers
    • DNS Domain name
  • Policies
    • Allows the admin to assign specific ip ranges to certain devices
      • printers
      • ip phones

DHCP Reservations

21: https://www.udemy.com/windows-server-2016/learn/v4/t/lecture/6048010?start=0

  • To set a reserved IP, you need the MAC address of the device.
    • C:\ getmac
    • 02-BB-8D-44-3D-3C
  • On the DC:
    • Tools > DHCP
    • Expand IPv4 > RClick Reservations > New Reservation
      • Reservations name:
      • IP address: This is the IP you are reserving from your scope
      • MAC: (From above getmac command)
      • Desc: whateva
      • Supported types
        • (*) Both
        • DHCP
        • Bootp (Bootstrap Protocol)
          • Only works on boot and does not work after the client is running

 

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