Simulasi VPN dengan Packet Tracert

-----------------------------------------------------------------------
      R1
-----------------------------------------------------------------------
Router>enable 
Router(config)#hostname R1
R1(config)#interface fa0/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#no shutdown 
R1(config-if)#exit

R1(config)#interface fa0/1
R1(config-if)#ip address 1.0.0.1 255.0.0.0
R1(config-if)#no shutdown 
R1(config)#exit

R1#copy running-config startup-config 
Destination filename [startup-config]? 
Building configuration...
[OK]
-----------------------------------------------------------------------
Routing
-----------------------------------------------------------------------
R1(config)#ip route 0.0.0.0 0.0.0.0 1.0.0.2
R1(config)#exit
========================
R2
========================
Router>enable 
Router#configure t
Router(config)#hostname R2
R2(config)#int fa0/0
R2(config-if)#ip address 1.0.0.2 255.0.0.0
R2(config-if)#no shutdown 
R2(config-if)#exit

R2(config)#int fa0/1
R2(config-if)#ip address 2.0.0.1 255.0.0.0
R2(config-if)#no shutdown 
R2(config-if)#exit
R2(config)#exit

R2#copy running-config startup-config 
Destination filename [startup-config]? 
Building configuration...
[OK]
R2#
-----------------------------------------------------------------------
    Routing
-----------------------------------------------------------------------
R2(config)#ip route 0.0.0.0 0.0.0.0 1.0.0.1
R2(config)#ip route 0.0.0.0 0.0.0.0 2.0.0.2
R2(config)#exit

R2#show ip route 

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

       * - candidate default, U - per-user static route, o - ODR

       P - periodic downloaded static route

Gateway of last resort is 1.0.0.1 to network 0.0.0.0

C    1.0.0.0/8 is directly connected, FastEthernet0/0

C    2.0.0.0/8 is directly connected, FastEthernet1/0

S*   0.0.0.0/0 [1/0] via 1.0.0.1

               [1/0] via 2.0.0.2

R2#copy running-config startup-config 

R2#ping 192.168.1.2

-----------------------------------------------------------------------

R3

-----------------------------------------------------------------------

Router>enable 

Router#configure terminal 

Router(config)#hostname R3

R3(config)#int fa0/0

R3(config-if)#ip address 2.0.0.2 255.0.0.0

R3(config-if)#no shutdown 

R3(config-if)#exit

R3(config)#int fa0/1

R3(config-if)#ip address 192.168.2.1 255.255.255.0

R3(config-if)#no shutdown 

R3(config-if)#exit

R3(config)#exit

R3#copy running-config startup-config 

-----------------------------------------------------------------------

Routing

-----------------------------------------------------------------------

R3(config)#ip route 0.0.0.0 0.0.0.0 2.0.0.1

R3(config)#exit

R3#

R3#copy running-config startup-config 

-----------------------------------------------------------------------

PC0

-----------------------------------------------------------------------

PC>tracert 192.168.2.2

Tracing route to 192.168.2.2 over a maximum of 30 hops: 

  1   0 ms      0 ms      0 ms      192.168.1.1

  2   *         0 ms      *         Request timed out.

  3   0 ms      0 ms      0 ms      2.0.0.2

  4   0 ms      0 ms      0 ms      192.168.2.2

Trace complete.

-----------------------------------------------------------------------

CREATE INTERFACE TUNNEL R1 dan R3

-----------------------------------------------------------------------

R1(config)#interface tunnel ?

  <0-2147483647>  Tunnel interface number

R1(config)#interface tunnel 10

R1(config-if)#ip address 172.16.1.1 255.255.0.0

R1(config-if)#tunnel source fa0/1

R1(config-if)#tunnel destination 2.0.0.2

R1(config-if)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel10, changed state to up

R1(config-if)#no shutdown 

R1(config-if)#exit

R1(config)#exit

R1#copy running-config startup-config 

----------------------------------------------------------------------

R3(config)#interface tunnel 20

R3(config-if)#

%LINK-5-CHANGED: Interface Tunnel20, changed state to up

R3(config-if)#ip address 172.16.1.2 255.255.0.0

R3(config-if)#tunnel source fa0/0

R3(config-if)#tunnel destination 1.0.0.1

R3(config-if)#no shutdown 

R3(config-if)#exit

R3(config)#exit

R3#copy running-config startup-config 

R3#ping 172.16.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 0/0/1 ms

R1#ping 172.16.1.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.1.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 0/0/0 ms

R1#

-----------------------------------------------------------------------

vpn routing R1 & R3

-----------------------------------------------------------------------

R1(config)#ip rout?

route  routing  

R1(config)#ip route 192.168.2.0 255.255.255.0 172.16.1.2

R3(config)#ip route 192.168.1.0 255.255.255.0 172.16.1.1

-----------------------------------------------------------------------

  Cek koneksi dari PC2

-----------------------------------------------------------------------

PC>tracert 192.168.1.2

Tracing route to 192.168.1.2 over a maximum of 30 hops: 

  1   1 ms      0 ms      0 ms      192.168.2.1

  2   0 ms      0 ms      0 ms      172.16.1.1

  3   0 ms      0 ms      0 ms      192.168.1.2

Trace complete.

-------

PC1

-------

PC>tracert 192.168.2.2

Tracing route to 192.168.2.2 over a maximum of 30 hops: 

  1   0 ms      0 ms      0 ms      192.168.1.1

  2   0 ms      0 ms      0 ms      172.16.1.2

  3   0 ms      0 ms      0 ms      192.168.2.2

Trace complete.

PC>

======================

R1#show interfaces tunnel 10

Tunnel10 is up, line protocol is up (connected)

  Hardware is Tunnel

  Internet address is 172.16.1.1/16

  MTU 17916 bytes, BW 100 Kbit/sec, DLY 50000 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation TUNNEL, loopback not set

  Keepalive not set

  Tunnel source 1.0.0.1 (FastEthernet0/1), destination 2.0.0.2

  Tunnel protocol/transport GRE/IP

    Key disabled, sequencing disabled

    Checksumming of packets disabled

  Tunnel TTL 255

  Fast tunneling enabled

  Tunnel transport MTU 1476 bytes

  Tunnel transmit bandwidth 8000 (kbps)

  Tunnel receive bandwidth 8000 (kbps)

  Last input never, output never, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 1

  Queueing strategy: fifo

  Output queue: 0/0 (size/max)

  5 minute input rate 0 bits/sec, 0 packets/sec

 --More-- 

VLAN

 

file : Gdrive

Switch(config)#hostname S1

S1(config)#vlan 10

S1(config-vlan)#name student
S1(config-vlan)#exit
S1(config)#vlan 20
S1(config-vlan)#name admin
S1(config-vlan)#end
S1#copy running-config startup-config
S1#

S1(config)#interface range fa0/1-fa0/9
S1(config-if-range)#switchport mode access
S1(config-if-range)#switchport access vlan 10
S1(config-if-range)#exit

 
S1(config)#interface range fa0/10-fa0/15
S1(config-if-range)#switchport mode access
S1(config-if-range)#switchport access vlan 20
S1(config-if-range)#end
S1#copy running-config startup-config

S1#sh vlan

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/16, Fa0/17, Fa0/18, Fa0/19
                                                Fa0/20, Fa0/21, Fa0/22, Fa0/23
                                                Fa0/24, Gig0/1, Gig0/2
10   student                          active    Fa0/1, Fa0/2, Fa0/3, Fa0/4
                                                Fa0/5, Fa0/6, Fa0/7, Fa0/8
                                                Fa0/9
20   admin                            active    Fa0/10, Fa0/11, Fa0/12, Fa0/13
                                                Fa0/14, Fa0/15

S1(config)#
S1(config)#int Gig0/1
S1(config-if)#switchport mode trunk
S1(config-if)#switchport trunk allowed vlan all
S1(config-if)#end
S1#copy running-config startup-config 

-----

Switch(config)#hostname S2
S2(config)#vlan 10
S2(config-vlan)#name student
S2(config-vlan)#exit
S2(config)#vlan 20
S2(config-vlan)#name admin
S2(config-vlan)#end
S2#copy running-config startup-config

S2(config)#interface range fa0/1-fa0/9
S2(config-if-range)#switchport mode access
S2(config-if-range)#switchport access vlan 10
S2(config-if-range)#exit

S2(config)#interface range fa0/10-fa0/15
S2(config-if-range)#switchport mode access
S2(config-if-range)#switchport access vlan 20
S2(config-if-range)#end
S2#copy running-config startup-config

S2#sh vlan

VLAN Name                             Status    Ports

---- -------------------------------- --------- -------------------------------

1    default                          active    Fa0/16, Fa0/17, Fa0/18, Fa0/19

                                                Fa0/20, Fa0/21, Fa0/22, Fa0/23
                                                Fa0/24, Gig0/1, Gig0/2

10   student                          active    Fa0/1, Fa0/2, Fa0/3, Fa0/4

                                                Fa0/5, Fa0/6, Fa0/7, Fa0/8

                                                Fa0/9

20   admin                            active    Fa0/10, Fa0/11, Fa0/12, Fa0/13

                                                Fa0/14, Fa0/15

Dynamic Routing Dengan OSPF Menggunakan Multi Area

 

file : Gdrive

R0(config)#router ospf 1
R0(config-router)#network 192.168.200.16 0.0.0.15 area 0
R0(config-router)#network 172.2.1.4 0.0.0.3 area 0
R0(config-router)#network 172.2.1.8 0.0.0.3 area 0
R0(config-router)#end

R1(config)#router ospf 1
R1(config-router)#network 172.2.1.4 0.0.0.3 area 0
R1(config-router)#network 172.2.1.16 0.0.0.3 area 1
R1(config-router)#network 192.168.10.0 0.0.0.255 area 1
R1(config-router)#network 172.2.1.12 0.0.0.3 area 0
R1(config-router)#end

R2(config)#router ospf 1
R2(config-router)#network 172.2.1.16 0.0.0.3 area 1
R2(config-router)#network 192.168.20.0 0.0.0.255 area 1
R2(config-router)#end

R3(config)#router ospf 1
R3(config-router)#network 172.2.1.8 0.0.0.3 are
R3(config-router)#network 172.2.1.8 0.0.0.3 area 0
R3(config-router)#network 172.2.1.12 0.0.0.3 area 0
R3(config-router)#network 192.168.30.0 0.0.0.255 area 2
R3(config-router)#network 172.2.1.20 0.0.0.3 area 2
R3(config-router)#end

R4(config)#router ospf 1
R4(config-router)#network 172.2.1.20 0.0.0.3 area 2
R4(config-router)#network 192.168.40.0 0.0.0.255 area 2
R4(config-router)#end

R1#sh ip route 
     172.2.0.0/30 is subnetted, 5 subnets
C       172.2.1.4 is directly connected, Serial2/0
O       172.2.1.8 [110/128] via 172.2.1.5, 00:14:02, Serial2/0
C       172.2.1.12 is directly connected, FastEthernet0/0
C       172.2.1.16 is directly connected, Serial3/0
O IA    172.2.1.20 [110/192] via 172.2.1.5, 00:03:04, Serial2/0
C    192.168.10.0/24 is directly connected, FastEthernet1/0
O    192.168.20.0/24 [110/65] via 172.2.1.18, 00:07:52, Serial3/0
O IA 192.168.30.0/24 [110/129] via 172.2.1.5, 00:03:33, Serial2/0
O IA 192.168.40.0/24 [110/193] via 172.2.1.5, 00:00:46, Serial2/0
     192.168.200.0/28 is subnetted, 1 subnets
O       192.168.200.16 [110/65] via 172.2.1.5, 00:14:02, Serial2/0

R0#sh ip route 
     172.2.0.0/30 is subnetted, 5 subnets
C       172.2.1.4 is directly connected, Serial2/0
C       172.2.1.8 is directly connected, Serial3/0
O IA    172.2.1.12 [110/65] via 172.2.1.6, 00:11:41, Serial2/0
                   [110/65] via 172.2.1.10, 00:05:01, Serial3/0
O IA    172.2.1.16 [110/128] via 172.2.1.6, 00:13:31, Serial2/0
O IA    172.2.1.20 [110/128] via 172.2.1.10, 00:03:54, Serial3/0
O IA 192.168.10.0/24 [110/65] via 172.2.1.6, 00:12:54, Serial2/0
O IA 192.168.20.0/24 [110/129] via 172.2.1.6, 00:08:37, Serial2/0
O IA 192.168.30.0/24 [110/65] via 172.2.1.10, 00:04:23, Serial3/0
O IA 192.168.40.0/24 [110/129] via 172.2.1.10, 00:01:36, Serial3/0
     192.168.200.0/28 is subnetted, 1 subnets
C       192.168.200.16 is directly connected, FastEthernet4/0

Dynamic Routing Dengan OSPF

OSPF adalah sebuah routing protocol standard terbuka yang telah diimplementasikan oleh sejumlah besar vendor jaringan, termasuk Cisco. Jika memiliki banyak router dari berbagai vendor maka salah satu pilihan yang baik adalah ospf.

Ospf bekerja dengan sebuah algoritma Djikstra. Pertama sebuah pohon jalur terpendek (shortest path tree) akan dibangun, dan kemudian routing table akan diisi dengan jalur-jalur terbaik yang dihasilkan dari pohon tersebut. OSPF mendukung multiple route dengan cost (biaya) yang sama ke tujuan yang sama.

ospf seharusnya seharusnya dirancang dengan cara heirarkis, yang pada dasarnya berarti bahwa sebuah internetwork yang besar dapat dipecah menjadi internetwork-internetwork yang lebih kecil. Alasan untuk menerapkan OSPF dalam rancangan hierarkis (topologi) antara lain :

- untuk mengurangi overhead (waktu pemrosesan) routing

- untuk mempercepat convergence

- untuk membatasi ketidakstabilan network di sebuah area

Contoh Rancangan OSPF

gambar di atas menunjukkan sebuah rancangan sederhana khas ospf. Setiap router terhubung ke backbone yang disebut area 0 atau area backbone. OSPF harus memiliki area 0 dan semua router harus terhubung ke area ini jika memungkinkan, tetapi router-router yang menghubungkan area-area lain ke backbone di dalam sebuah AS disebut Area Border Routerss (ABRs). Meskipun demikian, paling sedikit satu interface harus berada di area 0.

= = =

MENGKONFIGURASI OSPF

IP address antar router tidak menerapkan VLSM untuk alokasi IP Address

=========================================
IP ADD RA
==========================================
Router>ena
Router#config t
Router(config)#hostname RA
RA(config)#int gigabitEthernet 0/0
RA(config-if)#ip address 192.168.20.1 255.255.255.0
RA(config-if)#no sh

RA(config-if)#exit
RA(config)#int gigabitEthernet 0/1
RA(config-if)#ip address 192.168.10.1 255.255.255.0
RA(config-if)#no sh
RA#copy running-config startup-config 

======================================

IP ADD RB

======================================

Router>ena
Router#config t
Router(config)#hostname RB
RB(config)#int gigabitEthernet 0/0
RB(config-if)#ip address 192.168.20.2 255.255.255.0
RB(config-if)#no sh

RB(config-if)#exit
RB(config)#int gigabitEthernet 0/1
RB(config-if)#ip address 192.168.40.1 255.255.255.0
RB(config-if)#no sh
RB(config-if)#exit
RB(config)#int gigabitEthernet 0/2

RB(config-if)#ip address 192.168.30.1 255.255.255.0
RB(config-if)#no sh
RB(config-if)#end
RB#copy running-config startup-config

================================

RC IP Add
===============================
Router>ena
Router#config t
Router(config)#hostname RC
RC(config)#int gigabitEthernet 0/0
RC(config-if)#ip address 192.168.40.2 255.255.255.0
RC(config-if)#no sh
RC(config-if)#exit

RC(config)#int gigabitEthernet 0/1
RC(config-if)#ip address 192.168.50.1 255.255.255.0
RC(config-if)#no shutdown 
RC(config-if)#end
RC#copy running-config startup-config

===================================

OSPF

===================================

RA#config t

RA(config)#router ospf 12

RA(config-router)#network 192.168.10.1 0.0.0.0 area 0

RA(config-router)#network 192.168.20.1 0.0.0.0 area 0

RA(config-router)#end

RA#copy running-config startup-config

RB#config t

RB(config)#router ospf 14

RB(config-router)#network 192.168.0.0 0.0.255.255 area 0

RB(config-router)#end

RB#copy running-config startup-config 

RC#configure terminal 

RC(config)#router ospf 20

RC(config-router)#network 192.168.40.0 0.0.0.255 area 0

RC(config-router)#network 192.168.50.0 0.0.0.255 area 0

RC(config-router)#end

RC#copy running-config startup-config 

===

RA#sh ip route 

     192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks

C       192.168.10.0/24 is directly connected, GigabitEthernet0/1

L       192.168.10.1/32 is directly connected, GigabitEthernet0/1

     192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks

C       192.168.20.0/24 is directly connected, GigabitEthernet0/0

L       192.168.20.1/32 is directly connected, GigabitEthernet0/0

O    192.168.30.0/24 [110/2] via 192.168.20.2, 00:03:55, GigabitEthernet0/0

O    192.168.40.0/24 [110/2] via 192.168.20.2, 00:03:55, GigabitEthernet0/0

O    192.168.50.0/24 [110/3] via 192.168.20.2, 00:02:52, GigabitEthernet0/0

Simulasi Static Routing dengan Packet Tracert

 

R2

======

Fa1/0  192.168.30.1 /24

Fa0/0 192.168.1.6/ 30

Se3/0 192.168.1.14 /30

R0

=======

Fa1/0  192.168.10.1 /24

Fa0/0  192.168.1.5 /30

Se2/0  192.168.1.9 /30

PC0    192.168.10.2 /24

R1

=======

Fa1/0  192.168.20.1 /24

Se2/0  192.168.1.10 /30

Se3/0  192.168.1.13 /30

R0

=====

Router>enable 

Router#configure terminal 

Router(config)#hostname R0

R0(config)#interface fa1/0

R0(config-if)#ip address 192.168.10.1 255.255.255.0

R0(config-if)#no shutdown 

R0(config-if)#exit

R0(config)#interface fa0/0

R0(config-if)#ip address 192.168.1.5 255.255.255.252

R0(config-if)#no shutdown 

R0(config)#interface se2/0

R0(config-if)#ip address 192.168.1.9 255.255.255.252

R0(config-if)#no shutdown 

R0(config-if)#end

R0#copy running-config startup-config 

Destination filename [startup-config]? 

Building configuration...

R1

=====

Router>enable 

Router#configure terminal 

Router(config)#hostname R1

R1(config)#interface fa1/0

R1(config-if)#ip address 192.168.20.1 255.255.255.0

R1(config-if)#no shutdown 

R1(config-if)#exit

R1(config)#interface se2/0

R1(config-if)#ip address 192.168.1.10 255.255.255.252

R1(config-if)#no shutdown 

R1(config-if)#exit

R1(config)#interface se3/0

R1(config-if)#ip address 192.168.1.13 255.255.255.252

R1(config-if)#no shutdown 

R1(config-if)#exit

R1(config)#end

R1#copy running-config startup-config 

R2

=============

Router>enable 

Router#configure terminal 

Router(config)#hostname R2

R2(config)#interface fa1/0

R2(config-if)# ip address 192.168.30.1 255.255.255.0

R2(config-if)#no shutdown 

R2(config-if)#exit

R2(config)#interface fa0/0

R2(config-if)#ip address 192.168.1.6 255.255.255.252

R2(config-if)#no shutdown 

R2(config-if)#exit

R2(config)#interface se3/0

R2(config-if)#ip address 192.168.1.14 255.255.255.252

R2(config-if)#no shutdown 

R2(config-if)#end

R2#copy running-config startup-config 

=========================

Static Routing

=========================

Pada R0, rute menuju network di bawah R2 melalui dua jalur (1 sebagai back up), yaitu melalui 192.168.1.6 dan 192.168.1.10 (R1)

R0>enable 

R0#configure terminal 

R0(config)#ip route 192.168.30.0 255.255.255.0 192.168.1.6

R0(config)#ip route 192.168.30.0 255.255.255.0 192.168.1.10

R0(config)#ip route 192.168.20.0 255.255.255.0 192.168.1.10

R0(config)#ip route 192.168.1.12 255.255.255.252 192.168.1.10

R0(config)#end

R0#copy running-config startup-config 

R1>enable 

R1#configure 

R1(config)#ip route 192.168.10.0 255.255.255.0 192.168.1.9

R1(config)#ip route 192.168.30.0 255.255.255.0 192.168.1.14

R1(config)#end

R1#copy running-config startup-config 

R2#configur

R2(config)#ip route 192.168.10.0 255.255.255.0 192.168.1.13

R2(config)#ip route 192.168.1.8 255.255.255.252 192.168.1.13

R2(config)#ip route 192.168.20.0 255.255.255.0 192.168.1.13

R2(config)#end

R2#copy running-config startup-config 

------

R0#show ip route 

Gateway of last resort is not set

     192.168.1.0/30 is subnetted, 3 subnets

C       192.168.1.4 is directly connected, FastEthernet0/0

C       192.168.1.8 is directly connected, Serial2/0

S       192.168.1.12 [1/0] via 192.168.1.10

C    192.168.10.0/24 is directly connected, FastEthernet1/0

S    192.168.20.0/24 [1/0] via 192.168.1.10

S    192.168.30.0/24 [1/0] via 192.168.1.6

                     [1/0] via 192.168.1.10

R1#show ip route 

     192.168.1.0/30 is subnetted, 2 subnets

C       192.168.1.8 is directly connected, Serial2/0

C       192.168.1.12 is directly connected, Serial3/0

S    192.168.10.0/24 [1/0] via 192.168.1.9

C    192.168.20.0/24 is directly connected, FastEthernet1/0

S    192.168.30.0/24 [1/0] via 192.168.1.14

Class Full Network - Subnetting Alamat Class C

Contoh Subnetting untuk alamat Class C

Contoh 1
Alamat Network = 192.168.10.0

Subnet Mask  = /26 (255.255.255.192)

Menghitung jumlah subnet dan host yang valid

Perhatikan bit oktet ke 4 pada subnet mask : 11000000, menunjukkan alokasi subnet 2 bit (bernilai 1) dan alokasi host 6 bit (bernilai 0)

• Jumlah subnet valid = 2^2 -2 = 2 subnet, jika bit bernilai 1 di variasikan maka didapatkan : 11,10,01 dan 00. Karena tidak boleh semua bit bernilai 1 dan bernilai 0 sehingga jumlah subnet yang valid di kurangi 2 (2^2 -2)
• Blog subnet. dari variasi nilai bit (yang bernilai 1) blog subnet yang valid adalah : 10 (128) dan 01 (64). atau dengan cara cepat
• 256 - 192 = 64, dan kelipatannya yaitu 64+ 64= 128
• jadi alamat blog subnet yang valid adalah 64 dan 128
• Jumlah host tiap subnet yang valid. Jumlah host yang valid adalah variasi dari semua bit bernilai 0 (6 bit tsb) kecuali semau bit bernilai 1 dan semua bit bernilai 0. atau dengan cara cepat :
• 2^6 - 2 = 60 host tiap subnet.

Subnet                192.168.10.64         192.168.10.128

Host pertama      192.168.10.65         192.168.10.129

Host terakhir       192.168.10.126       192.168.10.190

Broadcast           192.168.10.127       192.168.10.191

Class Full Network - Subnetting Alamat Class B

Pada tulisan ini akan diberikan beberapa contoh untuk subnetting alamat Class B

1. Alamat network : 172.16.0.0. Subnet mask  = /18 (255.255.192.0)

Perhatikan oktet ke 3 dan ke 4pada subnet mask 11000000.00000000. alokasi untuk subnet = 2 bit dan alokasi host = 14 bit

• jumklah subnet yang valid = 2^2 - 2 = 2
• jumlah host setiap subnet = 2^14 - 2 = 16.382
• Blok subnet yang valid = 256 - 192 = 64, 64 + 64=128

Subnet             172.16.64.0           172.16.128.0
host pertama    172.16.64.1           172.16.128.1
Host terakhir    172.16.127.254     172.16.192.254

Broadcast        172.16.127.255     172.16.192.254 

2. Alamat network : 172.16.0.0. Subnet mask  = /20 (255.255.240.0)

Perhatikan oktet ke 3 dan ke 4pada subnet mask 11110000.00000000. alokasi untuk subnet = 4 bit dan alokasi host = 12 bit.

• jumklah subnet yang valid = 2^4 - 2 = 14
• jumlah host setiap subnet = 2^12 - 2 = 4094
• Blok subnet yang valid = 256 - 240 =16, 32, 48.....dst

tiga subnet pertama

Subnet                 172.16.16.0        172.16.32.0          172.16.48.0        ......

host pertama        172.16.16.1        172.16.32.1          172.16.48.1        ......

Host terakhir        172.16.31.254    172.16.47.254      172.16.63.254    .....

Broadcast            172.16.31.255    172.16.47.254      172.16.63.255    ......

3. Alamat network : 172.16.0.0. Subnet mask  = /26 (255.255.255.192) 

Perhatikan oktet ke 3 dan ke 4pada subnet mask 11111111.11000000. alokasi untuk subnet = 10 bit dan alokasi host = 6 bit

• jumklah subnet yang valid = 2^10 - 2 = 1022
• jumlah host setiap subnet = 2^6 - 2 = 62
• Blok subnet yang valid = 256 - 192 = 64 dan 128. Dan selama semua bit subnet pada oktet ke 3 tidak off ( bernilai 0) semuanya, maka subnet 0 di oktet ke 4 menjadi valid, selama bit subnet di oktet ke 3 tidak semuanya on (bernilai 1) maka 192 adalah valid di oktet ke 4 sebagai sebuah subnet.

Subnet             172.16.0.64     172.16.0.128    172.16.0.192    172.16.1.0     172.16.1.64     ......

host pertama    172.16.0.65     172.16.0.129    172.16.0.193    172.16.1.1     172.16.1.65      ......

Host terakhir    172.16.0.126   172.16.0.190    172.16.0.254    172.16.1.62   172.16.1.126    .....

Broadcast        172.16.0.127   172.16.0.191    172.16.0.255    172.16.1.63    172.16.1.127    ......