Inter-VLAN Routing con switch Layer 3, VTP e DHCP Relay
Caratteristiche generali
- Vlan ID 2 "Server", rete IP 192.168.2.0/24, pool DHCP da 192.168.2.101 a 192.168.2.200, gateway 192.168.2.254
- Vlan ID 3 "Client", rete IP 192.168.3.0/24, , pool DHCP da 192.168.3.101 a 192.168.3.200, gateway 192.168.3.254
- Vlan ID 4 "Stampanti", rete IP 192.168.4.0/24, , pool DHCP da 192.168.4.101 a 192.168.4.200, gateway 192.168.4.254
- Configurazione VTP (versione 2)
- Switch sw0: VTP server
- Switch sw1 e sw2: VTP client
- Dominio VTP: azienda
- Password VTP: 123456
- I tre pool DHCP sono configurati all'interno del server 192.168.2.1, il quale assegna indirizzi agli host delle VLAN 3 e 4 mediante DHCP Relay. Lo switch Layer 3 svolge la funzione di "intermediario" nella comunicazione tra server DHCP e client non appartenenti al medesimo dominio di broadcast (DHCP Relay Agent)
Soluzione (.pkt)
Configurazione dei dispositivi di rete
sw0# configure terminal
sw0(config)# vlan 2
sw0(config-vlan)# name Server
sw0(config-vlan)# exit
sw0(config)# vlan 3
sw0(config-vlan)# name Client
sw0(config-vlan)# exit
sw0(config)# vlan 4
sw0(config-vlan)# name Stampanti
sw0(config-vlan)# exit
sw0(config)# interface gi1/0/1
sw0(config-if-range)# switchport mode trunk
sw0(config-if-range)# exit
sw0(config)# interface range gi1/0/2
sw0(config-if-range)# switchport mode trunk
sw0(config-if-range)# end
sw0# show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
...
2 Server active
3 Client active
4 Stampanti active
...
sw0# show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gig1/0/1 on 802.1q trunking 1
Gig1/0/2 on 802.1q trunking 1
Port Vlans allowed on trunk
Gig1/0/1 1-1005
Gig1/0/2 1-1005
Port Vlans allowed and active in management domain
Gig1/0/1 1,2,3,4
Gig1/0/2 1,2,3,4
Port Vlans in spanning tree forwarding state and not pruned
Gig1/0/1 1,2,3,4
Gig1/0/2 1,2,3,4
! Configurazione VTP
sw0(config)# vtp mode server
sw0(config)# vtp domain azienda
sw0(config)# vtp password 123456
sw0(config)# vtp version 2
sw0(config)# end
sw0# show vtp status
VTP Version capable : 1 to 2
VTP version running : 2
VTP Domain Name : azienda
VTP Pruning Mode : Disabled
VTP Traps Generation : Disabled
...
VTP Operating Mode : Server
Maximum VLANs supported locally : 1005
Number of existing VLANs : 8
Configuration Revision : 13
...
sw0# configure terminal
!! Abilitazione dell'IP routing
sw0(config)# ip routing
! Configurazione delle SVI (Switch Virtual Interface)
sw0(config)# interface vlan 2
sw0(config-if)# ip address 192.168.2.254 255.255.255.0
sw0(config-if)# exit
! Per le VLAN 3 e 4 si attiva anche il DHCP Relay Agent in modo
! da inoltrare i messaggi DHCP sul server DHCP 192.168.2.1
! (il server DHCP deve avere un pool distinto per ciascuna VLAN)
sw0(config)# interface vlan 3
sw0(config-if)# ip address 192.168.3.254 255.255.255.0
sw0(config-if)# ip helper-address 192.168.2.1
sw0(config-if)# exit
sw0(config)# interface vlan 4
sw0(config-if)# ip address 192.168.4.254 255.255.255.0
sw0(config-if)# ip helper-address 192.168.2.1
sw0(config-if)# exit
! Esegue il comando "show" senza uscire dalla modalità di configurazione
sw0(config)# do show ip route
...
C 192.168.2.0/24 is directly connected, Vlan2
C 192.168.3.0/24 is directly connected, Vlan3
C 192.168.4.0/24 is directly connected, Vlan4
! Configurazione dell'interfaccia "routed"
! per il collegamento punto-punto al router
sw0(config)# interface gi1/0/3
sw0(config-if)# no switchport
sw0(config-if)# ip address 192.168.200.2 255.255.255.252
sw0(config-if)# exit
! Impostazione della default route
sw0(config)# ip route 0.0.0.0 0.0.0.0 192.168.200.1
sw0(config)# end
sw0# show ip route
...
C 192.168.2.0/24 is directly connected, Vlan2
C 192.168.3.0/24 is directly connected, Vlan3
C 192.168.4.0/24 is directly connected, Vlan4
192.168.200.0/30 is subnetted, 1 subnets
C 192.168.200.0 is directly connected, GigabitEthernet1/0/3
S* 0.0.0.0/0 [1/0] via 192.168.200.1
sw0# copy running-config startup-config
sw1# configure terminal
sw1(config)# vtp mode client
sw1(config)# vtp domain azienda
sw1(config)# vtp password 123456
sw1(config)# vtp version 2
sw1(config)# interface fa0/1
sw1(config-if)# switchport mode access
sw1(config-if)# switchport access vlan 2
sw1(config-if)# exit
sw1(config)# interface fa0/2
sw1(config-if)# switchport mode access
sw1(config-if)# switchport access vlan 3
sw1(config-if)# exit
sw1(config)# interface fa0/3
sw1(config-if)# switchport mode access
sw1(config-if)# switchport access vlan 4
sw1(config)# end
! L'interfaccia gi0/1 di default è dinamica (auto), diventa
! automaticamente trunk se collegata a un'altra porta trunk
sw1# show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
...
2 Server active Fa0/1
3 Client active Fa0/2
4 Stampanti active Fa0/3
...
sw1# show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gig0/1 auto n-802.1q trunking 1
Port Vlans allowed on trunk
Gig0/1 1-1005
Port Vlans allowed and active in management domain
Gig0/1 1,2,3,4
Port Vlans in spanning tree forwarding state and not pruned
Gig0/1 1,2,3,4
sw1# show vtp status
VTP Version capable : 1 to 2
VTP version running : 2
VTP Domain Name : azienda
VTP Pruning Mode : Disabled
VTP Traps Generation : Disabled
Device ID : 000A.41B0.8E00
Configuration last modified by 0.0.0.0 at 3-1-93 00:05:55
Feature VLAN :
--------------
VTP Operating Mode : Client
Maximum VLANs supported locally : 255
Number of existing VLANs : 8
Configuration Revision : 13
...
sw1# copy running-config startup-config
La configurazione dello switch sw2 è identica a quella dello switch sw1.
R0# configure terminal
R0(config)# interface gi0/0
R0(config-if)# ip address 192.168.200.1 255.255.255.252
R0(config-if)# no shutdown
R0(config-if)# exit
! Interfaccia per testare la raggiungibilità della rete Internet
R0(config)# interface loopback 1
R0(config-if)# ip address 1.2.3.1 255.255.255.0
R0(config-if)# exit
! Regole di route per raggiungere gli host della rete LAN
R0(config)# ip route 192.168.2.0 255.255.255.0 192.168.200.2
R0(config)# ip route 192.168.3.0 255.255.255.0 192.168.200.2
R0(config)# ip route 192.168.4.0 255.255.255.0 192.168.200.2
R0(config)# end
R0# copy running-config startup-config