Download (DHCP)

Module 01:
Dynamic Host Configuration
Protocol (DHCP)
Why Use DHCP?
DHCP는 TCP/IP를 자동 구성을 사용함으로써 구성상의 불편함과 복잡함을
해소 하였다.
Manual TCP/IP Configuration
IP addresses를 User가 직접 지정
잘못된 IP address로 구성할 수 있는
가능성이 있다.
잘못된 network 구성은 Network
issues를 초래한다
Computer의 Network 정보의
빈번한 변경은 관리 작업의 부하를
초래
Automatic TCP/IP Configuration
IP addresses를 자동으로 client
computers에 부여
Clients 에게 정확한 network구성
정보를 제공한다
Client 의 Network 구성 정보를
자동으로 Update를 제공한다.
Network 상에 발생 할 수 있는
문제점을 제거
Network Service -2
How DHCP Allocates IP Addresses
Non-DHCP Client:
Static IP
configuration
DHCP Client2:
IP configuration
from DHCP server
Lease Renewal
Lease Generation
DHCP Server
DHCP Client1:
IP configuration
from DHCP server
DHCP
Database
IP Address1: Leased to DHCP Client1
IP Address2: Leased to DHCP Client2
IP Address3: Available to be leased
Network Service -3
How the DHCP Lease Generation Process Works
DHCP
Server2
DHCP
Server1
DHCP
Client
1
DHCP client 가 broadcasts 로 DHCPDISCOVER packet 요청
2
DHCP servers는 broadcast로 DHCPOFFER packet 응답
3
DHCP client 가 broadcasts 로 DHCPREQUEST packet 요청
4
DHCP Server1 broadcasts 로 DHCPACK packet을 응답
Network Service -4
How the DHCP Lease Renewal Process Works
DHCP
Server2
DHCP
Server2
DHCP
Server1
DHCP Client
DHCP 50%
Clientof lease
duration has
expired
DHCP
Server1
1
2
DHCP client sends a DHCPREQUEST packet 87.5%
100%
50% of
of
oflease
lease
lease
duration has
DHCP Server1 sends a DHCPACK packet
expired
client
가 lease
50%가
지나면
갱신
요청을
Client
sends
a DHCPREQUEST
packet
If theDHCP
client
fails time
to
renew
its lease,
after
50%
of the한다,
lease만약
187.5%의
lease time 지나도록 갱신되지 않은 경우 lease
duration
has
expired,
then the
DHCP 다시
leaseIP
renewal
will
time이 만료 된
후 , DHCP
client는
정보를process
받기 위해
sends
DHCPACK
packet
2beginDHCP
againServer1
after 87.5%
ofathe
lease duration
has expired
broadcasting으로
DHCPDISCOVER
메시지를
보낸다.
Network Service -5
How a DHCP Server Service Is Authorized
DHCP
IP address가
DHCPServer1에
Server1는
domain
존재한다면,
DHCP
Client에게
IP
controller에게
DHCP servers
address를 제공할 수 있다.
인증 요청을 한다.
DHCP Server1
Domain
Controller
Authorized
Services DHCP
requests
Active
Directory
DHCP Server2
DHCP Client
Unauthorized
DHCP
Server2는
domain
DHCP
Server2
에 IP address를
인증된
DHCP
Server1로
부터
DHCP
가지고 있지 않다면
, DHCP
clients는
controller에게
DHCP
Server
인증
client는
IP
address
제공
받는다
.
IP address를
Service를
요청을
한다.받지 못한다
Does not service
DHCP requests
Active Directory domain로부터 DHCP Server 인증을 받아야 DHCP
client들에게 DHCP Server service를 할 수 있다
Network Service -6
Lesson: Configuring a DHCP Scope


What Are DHCP Scopes?
How to Configure a DHCP Scope
Network Service -7
What Are DHCP Scopes?
Scope(범위)란
DHCP 서비스를 사용하는 Subnet에서 관리 목적을
위해 컴퓨터의 IP addresses 그룹으로 묶은 것입니다
DHCP Server
LAN A
LAN B
Scope A
Scope B
Scope Properties

Network ID

Lease duration

Scope name

Subnet mask

Router

Exclusion range

Network IP
address range
Network Service -8
Lesson: Configuring a DHCP Reservation


What Is a DHCP Reservation?
How to Configure a DHCP Reservation
Network Service -9
What Is a DHCP Reservation?
Reservation란 특정 DHCP Client가 IP address의 영구적인 사용에 대비하여
특정한 IP address를 예약한 것을 말한다
Workstation 1
Subnet A
File and
Print Server
Subnet B
DHCP Server
Workstation 2
IP Address1: Leased to Workstation 1
IP Address2: Leased to Workstation 2
IP Address3: Reserved for File and Print Server
Network Service -10
Lesson: Configuring DHCP Options




What Are DHCP Options?
How DHCP Server, Scope, and Reserved Client Options Are
Applied
How DHCP Class-level Options Are Applied
How to Configure DHCP Options
Network Service -11
What Are DHCP Options?
DHCP options에서 configuration parameters들은 DHCP service가
clients에게 IP address와 default gateway를 제공한다.
DHCP Client
DHCP Client IP Configuration Data
Client’s IP address
Client’s subnet mask
DHCP options such as:
 Router’s IP address
 DNS server’s IP address
 WINS server’s IP address
 DNS domain name
DHCP Server
Network Service -12
How DHCP Server, Scope, and Reserved Client Options
Are Applied
DHCP Server
File and
Print Server
Windows 98
Scope A
Scope B
Router
Windows XP
Windows XP
DHCP option applied at the
reserved-client
server
scope levellevel
Network Service -13
How DHCP Class-level Options Are Applied
DHCP Server
File and
Print Server
Windows 98
Router
Router
Scope A
Scope B
Windows XP
Windows XP
DHCP option applied at the
class level
Network Service -14
Lesson: Configuring a DHCP Relay Agent





What Is a DHCP Relay Agent?
How a DHCP Relay Agent Works
How a DHCP Relay Agent Uses Hop Count
How a DHCP Relay Agent Uses Boot Threshold
How to Configure a DHCP Relay Agent
Network Service -15
What Is a DHCP Relay Agent?
DHCP relay agent 는 서로 다른 Subnet에 있는 Server와 Clinet 간에게
DHCP/BOOTP broadcasts 메시지를 relay를 하는 작은 프로그램이다.
DHCP Relay Agent
DHCP Server
Unicast
Broadcast
Broadcast
Subnet A
Subnet B
Routers
Non-RFC 1542
Compliant
Client
Client
Client
Client
Network Service -16
How a DHCP Relay Agent Works
DHCP Relay Agent
Client1
1
2
3
4
5
6
7
8
Client2
DHCP Server
Router
Non-RFC 1542 Compliant
Client3
Client1 broadcasts a DHCPDISCOVER packet
Relay agent forwards the DHCPDISCOVER message to the DHCP server
Server sends a DHCPOFFER message to the DHCP relay agent
Relay agent broadcasts the DHCPOFFER packet
Client1 broadcasts a DHCPREQUEST packet
Relay agent forwards the DHCPREQUEST message to the DHCP server
Server sends a DHCPACK message to the DHCP relay agent
Relay agent broadcasts the DHCPACK packet
Network Service -17
How a DHCP Relay Agent Uses Hop Count
The hop count threshold 는 DHCP Relay Agent Packet이 훼손 되지
않고 전달할 수 있는 routers 의 개수를 말한다.
DHCP Relay Agent 2
Hop Count = 2
DHCP Relay Agent 1
DHCP Server
Network Service -18
How a DHCP Relay Agent Uses Boot Threshold
boot threshold란 ? DHCP Client가 Address 요청 시 얼마 후에 응답 할
것인지를 지정하는 값이다.
DHCP Server 2
Boot Threshold
= 10 seconds
DHCP Relay Agent
Local DHCP
Server
DHCP Server 3
Network Service -19
Lab : IP Addressing by Using DHCP
1. Windows 2003 Server를 이용하여 DHCP
Server를 구성한 후 XP Client에 Address 할
당 내역을 확인한다.
2. Cisco Router를 이용하여 DHCP서버를 구성하
고 XP Client에서 확인한다.
3. 서버구성 내용
1.
2.
3.
4.
5.
6.
IP Address
Subnet Mask
Default-Gateway
DNS Server Address
Domain Name
Option 150
Network Service -20
LAB
Network Service -21