4/19 IP 주소 체계 및 클래스, 공인/사설 IP

naver.com : domain name

server : www

mail

cafe

blog

 

www.naver.com

mail.naver.com

cafe.naver.com

blog.naver.com

 

 

* Oracle VM VirtualBox 한글 안나올때 -> Alt키만 누르면 됨

* https://www.virtualbox.org/wiki/linux_Downloads 

 

first ip: Network Address, Host ID = 0

          routing table

last ip address : broadcast address (방송용 주소)

 

MAC Address length : 6byte=48bit 3byte(OUI)+3byte(P ID)

IP Address version 4 length : 4byte=32bit

2                                                     10

00000000.0000000.00000000.00000000 0.0.0.0

…..

11111111.11111111.11111111.11111111

255.255.255.255

2^7 + 2^6 + 2^5 + 2^4 + 2^3 + 2^2 + 2^1 + 2^0

= 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255

0~255 . 0~255 . 0~255 . 0~255

 

IP address = Network ID + Host ID

Network ID : same part , host ID : id

192.168.0.0 → first ip : Network Address , Host ID =0

routing table

192.168.0.1

192.168.0.2

192.168.0.100

192.168.0.200  192.168.0.1 ~ 192.168.0.254 // assgined

192.168.0.255 → last ip address : broadcast address(방송용 주소)

------------____ Host ID=1

 

Network ID , Host ID → subnetmask

Network ID → 1 , Host ID → 0

1111111.11111111.11111111.00000000 sm

255.255.255.0

 

* 8bit.8bit.8bit.8bit ->옥텟

8bit:0~255 -> 256개

 

※0000 0000 ->0

1111 1111->255  

=> 256

 

* 이진수 0~1 1+1 10

10진수 0~9 9+1 10

16진수 0~15 15+1 10 F+1->10

   ->Mac  0~9까지는 숫자, 10부터 문자로 표기(10 A  11 B  12 C  13 D  14 E  15 F)

IP주소 이진수->10진수

 

class

 

A  class : 1~ 127.x.x.x

     A class defualt subnetmask  255.0.0.0

B class 128 ~ 191.x.x.x

     B class default subnetmask 255.255.0.0

 

C  class 192~223.x.x.x

C classs defualt subnetmask 255.255.255.0

 

 

public IP Address → Public network

Private Ip address → Private network

 

0.0.0.0 all address

routing table : default route 0.0.0.0/0

 

- lo : Loopback

 

- 127.0.0.0 loopback

셀프 테스트 ping 127.0.0.1 ipv6 ::1

server web service → localhost

 

169.254.0.0 link local address

DHCP X – OS

224~239.0.0.0 : D class multicast address

240~254.0.0.0 : E class

255.255.255.255 (all addresss – broadcast)

 

- Host ID=0 Network address ex) 192.168.0.0

  Host ID=1 Broadcast address ex) 192.168.0.255

 

- private network address

 A 10.0.0.0/8  10.0.0.0 ~ 10.255.255.255 , 10.x.x.x (N1(네트워크가 1개)) ->10으로 시작하는건 다 사설임, 192.168 도 마찬가지

 B 172.16.0.0/12  172.16.0.0 ~ 172.31.255.255 172.16-31.x.x (N16(네트워크가 16개))

 C 192.168.0.0/16  192.168.0.0 ~ 192.168.255.255 (N256(네트워크가 256개))

 

1-32 : 32ea(개)

0-31 : 32ea

0-15 (16) , 16-31 (16)

* 문제 알아두기

1. OSI 7 Layer
2. Address 
1. Physical Address
2. Logical Address