- Fact:
- The most common (simplest)
IP host/node configuration
can be
automated by using:
- The Dynamic Host Configuration Protocol (DHCP)
- The most common (simplest)
IP host/node configuration
can be
automated by using:
- The
Dynamic Host Configuration Protocol (DHCP)
allows
an IP host/node to:
- obtain
a
unique IP-address
at boot time
Note:
- The node can determine its IP network ID because the IP network ID is a part of the IP address !!!
- obtain the IP-address of the default router on the network
- obtain
a
unique IP-address
at boot time
- Note:
- The DHCP protocol
works like a
reverse-ARP protocol:
- ARP finds the physical address for a given IP address
- DHCP finds (allocates) an IP address for a given physical (Ethernet) address
- The DHCP protocol
was develped from an
older protocol called
BOOTP
(Bootstrap Protocol)
See: click here
- The DHCP protocol
works like a
reverse-ARP protocol:
- The DHCP protocol is implemented
using a DHCP "server":
- DHCP server:
- DHCP server = a program that implements the DHCP protocol that responds to DHCP requests sent by (DHCP) clients
(A program that sends DHCP requests (to an DHCP server) is called a DHCP client)
Note:
- Many home routers:
has a built-in DHCP server (software !)
- 2 types of
IP address assignment methods:
- Static IP address assignment
- Dynamic IP address assignment
- Static IP address assignment:
- Static IP address assignment = a given computer is always assigned with the same IP address
- Implementation:
- In static
IP address assignment, the
DHCP server
will use:
- A static IP address table to maps a fixed set of physical addresses to IP addresses
Example:
- In static
IP address assignment, the
DHCP server
will use:
- Common scenarios that require a
static assignment:
- Servers (=
computers that
provides a specific service)
needs a fixed IP address
- Example: file servers
Servers can only be reached easily when its IP address does not change !!!
- Analogy: suppose the Pizza Delivery keeps changing its phone number.... they'll be out of business very soon !!!
- Computers that
have a higher level of trust
(= privilege)
use a fixed IP address
- In this case, the IP address is used as the identifier to gain access to special privileges.
- Servers (=
computers that
provides a specific service)
needs a fixed IP address
- Dynamic IP address assignment:
- Dynamic IP address assignment = a given computer can be assigned with different IP addresses at different times
- Implementation:
- In dynamic IP address assignment,
the
DHCP server
has a pool (set)
of IP address:
- The DHCP server will randomly select some unassigned IP address and assign the IP address to a computer
Example:
- In dynamic IP address assignment,
the
DHCP server
has a pool (set)
of IP address:
- When to use
dynamic IP address assignment:
- Dynamic IP address assignment is
used when a computer does
not provide any
special service
- The computer is as a user terminal to run applications (such as web browser, editor, etc....
- Dynamic IP address assignment is
used when a computer does
not provide any
special service