CompTIA A+ 220-1201 (2.4 - DHCP)

DCHP

• IPv4 address configuration used to be manual

- IP address, subnet mask, gateway, DNS servers,

NTP servers, etc.

• Needed a more automatic method

- Scale to thousands of systems

- Hands-off IP configurations

• Dynamic Host Configuration Protocol (DHCP)

- Initially released in 1997, updated through the years

- Provides automatic address / IP configuration

- Used for almost all devices

DHCP leases

• DORA

- A four-step process

• Discover

- Find a DHCP server

• Offer

- Get an offer

• Request

- Lock in the offer

• Acknowledge

- DHCP server confirmation

DHCP scopes

• Configured on the DHCP server

• IP address range

- And excluded addresses

• Subnet mask

• Lease durations

• Other scope options

- DNS server

- Default gateway

- VOIP servers

DHCP pools

• Grouping of IP addresses

- Each subnet has its own scope

- 192.168.1.0/24

- 192.168.2.0/24

- 192.168.3.0/24

- ...

• A scope is generally a single contiguous

pool of IP addresses

- DHCP exceptions can be made inside of the scope

Address reservation

• Address reservation

- Administratively configured

• Table of MAC addresses

- Each MAC address has a matching IP address

• Other names

- Static DHCP Assignment

- Static DHCP

- IP Reservation