TIL 0209 ~ 10 in Internship

IPv4

• 32bit, 8bit, 10진수, Octet 구분
• Network IP + Host IP => Class 주소체계
• Host 수
  • 2^h - 2

---

NAT

---

Classless

203.241.132.32/28
11001011.11110001.10000100.00100000
11111111.11111111.11111111.11110000 255.255.255.240
11001011.11110001.10000100.0010|0000
11001011.11110001.10000100.00100000 203.241.132.32
11001011.11110001.10000100.00101111 203.241.132.47
28 - 네트워크 bit수

1. Host수? 14
2. Subnetmask? 255.255.255.240
3. Network IP? 203.241.132.32
4. Broadcast IP? 203.241.132.47
5. IP scope? 203.241.132.33 ~ 203.241.132.46

203.241.132.32/30
11001011.11110001.10000100.00100000
11111111.11111111.11111111.11111100 255.255.255.252
11001011.11110001.10000100.001000|00
11001011.11110001.10000100.00100000 203.241.132.32
11001011.11110001.10000100.00100011 203.241.132.35

1. Host수? 2
2. Subnetmask? 255.255.255.252
3. Network IP? 203.241.132.32
4. Broadcast IP? 203.241.132.35
5. IP scope? 203.241.132.33 ~ 203.241.132.34

---

Subnetting

그렇다면 4개는?

200.1.1.0/26
11001000.00000001.00000001.00|000000
11111111.11111111.11111111.00|000000 0 ~ 63
11111111.11111111.11111111.01|000000 64 ~ 127
11111111.11111111.11111111.10|000000 128 ~ 191
11111111.11111111.11111111.11|000000 192 ~ 255
11111111.11111111.11111111.11|111111 255

종류

• FLSM
  • Fixed Length Subnet Mask
• VLSM
  • Variable Length Subnet Mask
  • subnetting 한 것을 또 다시 subnetting

---

Routing

• Distance Vector
  • 최소홉수
• Link state
  • 최소비용
• ADV (hybrid)
  • 대역폭, Delay 고려

Wildcardmask

Static Route

R0>en
R0#show ip route
R0(config)#ip route 200.2.2.0 255.255.255.0 12.12.12.2
R1(config)#ip route 200.1.1.0 255.255.255.0 12.12.12.1

PC>ping 200.2.2.10

Default Route

R0(config)#ip route 0.0.0.0 0.0.0.0 12.12.12.2
R1(config)#ip route 0.0.0.0 0.0.0.0 12.12.12.1

PC>ping 200.2.2.10

Router 실습과제1

R0(config)#ip route 0.0.0.0 0.0.0.0 10.10.10.1
R5(config)#ip route 0.0.0.0 0.0.0.0 40.40.40.1

R1(config)#ip route 23.23.23.0 255.255.255.0 12.12.12.2
R1(config)#ip route 34.34.34.0 255.255.255.0 12.12.12.2
R1(config)#ip route 40.40.40.0 255.255.255.0 14.14.14.4

R2(config)#ip route 10.10.10.0 255.255.255.0 12.12.12.1
R2(config)#ip route 14.14.14.0 255.255.255.0 12.12.12.1
R2(config)#ip route 34.34.34.0 255.255.255.0 23.23.23.3
R2(config)#ip route 40.40.40.0 255.255.255.0 23.23.23.3

R3(config)#ip route 10.10.10.0 255.255.255.0 23.23.23.2
R3(config)#ip route 12.12.12.0 255.255.255.0 23.23.23.2
R3(config)#ip route 40.40.40.0 255.255.255.0 34.34.34.4
R3(config)#ip route 14.14.14.0 255.255.255.0 34.34.34.4

R4(config)#ip route 10.10.10.0 255.255.255.0 14.14.14.1
R4(config)#ip route 12.12.12.0 255.255.255.0 14.14.14.1
R4(config)#ip route 23.23.23.0 255.255.255.0 34.34.34.3

Router RIP

R1(config)#router rip
R1(config-router)#version 2
R1(config-router)#network 10.10.10.0
R1(config-router)#network 12.12.12.0
R1(config-router)#network 14.14.14.0

R2(config)#router rip
R2(config-router)#ver 2
R2(config-router)#net 23.23.23.0
R2(config-router)#net 12.12.12.0

R3(config)#router rip
R3(config-router)#ver 2
R3(config-router)#net 23.23.23.0
R3(config-router)#net 34.34.34.0

R4(config)#router rip
R4(config-router)#ver 2
R4(config-router)#net 40.40.40.0
R4(config-router)#net 34.34.34.0
R4(config-router)#net 14.14.14.0

R4#show ip route

R0>ping 40.40.40.10
R0>traceroute 40.40.40.10

Router OSPF

R1(config)#router ospf 1
R1(config-router)#network 10.10.10.1 0.0.0.0 area 0
R1(config-router)#network 12.12.12.1 0.0.0.0 area 0
R1(config-router)#network 14.14.14.1 0.0.0.0 area 0

R2(config)#router ospf 2
R2(config-router)#network 23.23.23.2 0.0.0.0 ar 0
R2(config-router)#network 12.12.12.2 0.0.0.0 ar 0

R3(config)#router ospf 3
R3(config-router)#net 23.23.23.3 0.0.0.0 ar 0
R3(config-router)#net 34.34.34.3 0.0.0.0 ar 0

R4(config)#router ospf 4
R4(config-router)#net 40.40.40.1 0.0.0.0 ar 0
R4(config-router)#net 34.34.34.4 0.0.0.0 ar 0
R4(config-router)#net 14.14.14.4 0.0.0.0 ar 0

R4#show ip route
R0>ping 40.40.40.10
R0>traceroute 40.40.40.10

Inter-VLAN Routing

Switch(config)#int f0/1
Switch(config-if)#switchport mode trunk

Router(config)#int f0/1
Router(config-if)#no shutdown

Router(config-if)#int f0/1.1
Router(config-subif)#encapsulation dot1q 10
Router(config-subif)#ip addr 200.1.1.1 255.255.255.0

Router(config-subif)#int f0/1.2
Router(config-subif)#encap dot1q 20
Router(config-subif)#ip addr 200.2.2.1 255.255.255.0

VLAN Routing net2

Switch(config)#int vlan 10
Switch(config-if)#ip addr 200.1.1.1 255.255.255.0
Switch(config-if)#int vlan 20
Switch(config-if)#ip addr 200.2.2.1 255.255.255.0

Switch(config)#ip routing
Switch(config)#do show ip route

L3SW

Switch(config)#int f0/2
Switch(config-if)#no switchport
Switch(config-if)#ip addr 200.1.1.1 255.255.255.0

Switch(config-if)#int f0/1
Switch(config-if)#no switchport
Switch(config-if)#ip addr 200.2.2.1 255.255.255.0

Switch(config)#ip routing
Switch(config)#do show ip route

---

Access Control List - ACL

1. Top - Down Process
2. First Matching
3. 암묵적 Deny

ACL Standard

R1(config)#access-list 1 deny 40.40.40.0 0.0.0.255
R1(config)#access-list 1 permit any
R1(config)#int f0/0
R1(config-if)#ip access-group 1 out

R1#show access-list

ACL Extended

R0(config)#enable secret korea
R0(config)#line vty 0 4
R0(config-line)#password korea
R0(config-line)#login

R1(config)#no access-list 1
R1(config)#access-list 100 permit tcp 40.40.40.0 0.0.0.255 10.10.10.0 0.0.0.255 eq 23
R1(config)#int f0/0
R1(config-if)#ip access-group 100 out

R1(config)#no access-list 100
R1(config)#access-list 100 deny icmp any any
R1(config)#access-list 100 permit ip any any

ACL VTY

R0(config)#access-list 1 permit 40.40.40.10 0.0.0.0
R0(config)#line vty 0 4
R0(config-line)#access-class 1 in

---

NAT | PAT

---

이중화 프로토콜

HSRP | VRRP

• HSRP
  • CISCO
• VRRP
  • 표준
• GLBP
  • 표준

---

---

---

복습

1. Class 주소체계에서 172.16.3.10 의 네트워크 주소는 무엇인가요?

• B Class, 172.16.0.0

A : 1 ~ 126.0.0.0/8
B : 127 ~ 191.0.0.0/16
C : 192 ~ 223.0.0.0/24

2. 사설IP로 예약된 주소 범위는 무엇인가요?

• 10.0.0.0/8
• 172.16.0.0/12
• 192.168.0.0/16

3. 사설IP 주소를 인터넷연결시 공인IP 주소로 변환하는 기술은 무엇인가요?

• NAT - Network Address Translation

4. 203.241.132.32/26 의 서브넷 마스크값은 무엇입니까?

• 255.255.255.192
  203.241.132.32/29 의 호스트 주소수는 얼마입니까?
• 6개
  203.241.132.32/30 의 브로드캐스트 주소는 무엇입니까?
• 203.241.132.35

  11001011.11110001.10000100.000100|00 : Network 주소
  11001011.11110001.10000100.000100|11 : Broadcast 주소

203.241.132.1/28 의 사용가능한 IP 주소 범위는 무엇입니까?

• 203.241.132.1 - 203.241.132.14

  11001011.11110001.10000100.0000|0000 <=
  x
  < 11001011.11110001.10000100.0000|1111

Subnet 계산기

5. 10.1.1.1을 default router로 설정하는 명령은 무엇인가요?

• ip route 0.0.0.0 0.0.0.0 10.1.1.1

6. 다음을 설명하는 라우팅 프로토콜을 쓰세요.

• DV: 최소 홉수를 기준으로 RIP, IGRP
• ADV: 대역폭과 지연시간을 기준으로 EIGRP, BGP
• LS: 최소 Cost를 기준으로 OSPF, IS-IS

7. 최소비용으로 최적경로를 메트릭을 사용하는 라우팅 프로토콜은 무엇인가요?

• OSPF, IS-IS

8. 라우팅 프로토콜 AD 값을 쓰세요.

• Connected: 0
• Static: 1
• EIGRP: 90
• OSPF: 110
• RIP: 120

9. 라우팅 프로토콜 설명이 맞지 않은 것은 무엇인가요? c
a. RIPv1은 Classful만 지원한다.
b. EIGRP는 AS 번호가 일치해야 Neighbors 가 된다.
c. OSPF는 Process ID 번호가 일치해야 일치될 필요가 없다. Neighbors 가 된다.
d. BGP는 EGP이다.

10. 와일드카드마스크를 쓰세요

• 10.1.1.1/8 : 0.255.255.255
• 10.1.1.1/16 : 0.0.255.255
• 10.1.1.1/24 : 0.0.0.255
• 10.1.1.1/28 : 0.0.0.15
• 10.1.1.1/32 : 0.0.0.0