Helpful Hints about INE’s virtual lab environment:

• Save your configuration changes frequently in the event that you get locked out of a device or lose connectivity
• If you are suddenly logged out of the GNS3 lab environment and log back in again, you may see the prompt, “Another GNS3 instance is running, continue? (Y/N)”. Select “Yes”

• If you ever lose console access to one (or more) of your devices you will need to reboot the Ubuntu Virtual Machine that is hosting your GNS3 lab environment. To do this,

  • Minimize your GNS3 window
  • Open the “Terminal” app within the Ubuntu device

  

  • Type “reboot” within the Terminal window
  • Wait 20-30 seconds and then click the “Reconnect” option to log back in.

Solutions:

Because we have used different VLANs to connect the routers and the task is asking us to make them reachable, inter-VLAN routing should be in place to make them reachable. As we know, there should be at least one L3 device; that is, a router or L3-capable switch. So we are using R1 to perform inter-VLAN routing for VLAN 100 and VLAN 200. Make sure that the switchport connected to R1 is configured as static trunk because a router does not support DTP. Additionally, we must configure sub-interfaces on R1 on the basis of which VLANs we are trying to route to each other.

First, configure Sw1's Gig0/1 port as a trunk.

    Sw1>en
    Sw1#config t
    Enter configuration commands, one per line.  End with CNTL/Z.
    Sw1(config)#interface gig0/1
    Sw1(config-if)#switchport trunk encapsulation dot1q
    Sw1(config-if)#switchport mode trunk
    Sw1(config-if)#end
    Sw1#
    *Jul 27 17:07:50.275: %SYS-5-CONFIG_I: Configured from     console by console
    Sw1#
    Sw1#show interface gig0/1 switchport
    Name: Gi0/1
    Switchport: Enabled
    Administrative Mode: trunk
    Operational Mode: trunk
    Administrative Trunking Encapsulation: dot1q
    Operational Trunking Encapsulation: dot1q
    Negotiation of Trunking: On

Now configure R1 with the sub-interfaces and IP addressing for VLAN100 and VLAN200.

R1:
interface Gig0/0
 no ip address
 no shutdown
!
interface Gig0/0.100
 encapsulation dot1Q 100
 ip address 100.1.1.1 255.255.255.0
!
interface Gig0/0.200
 encapsulation dot1Q 200
 ip address 200.1.1.1 255.255.255.0

Set the default-gateway on R2, R3, and R4. Because we are using routers as the hosts, we must disable "ip routing" first and set the default gateway accordingly.

    R2:
    no ip routing
    !
    ip default-gateway 100.1.1.1

    R3:
    no ip routing
    !
    ip default-gateway 200.1.1.1

    R4:
    no ip routing
    !
    ip default-gateway 200.1.1.1

Verification

When configured, check the reachability between hosts in different VLANs.

    R2#sh ip route
    Default gateway is 100.1.1.1

    Host               Gateway           Last Use    Total     Uses  Interface
    ICMP redirect cache is empty

    R2#ping 200.1.1.4
    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 200.1.1.4, timeout is 2     seconds:
    .!!!!
    Success rate is 80 percent (4/5), round-trip min/avg/max =     36/36/36 ms

    R2#ping 200.1.1.3
    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 200.1.1.3, timeout is 2     seconds:
    .!!!!
    Success rate is 80 percent (4/5), round-trip min/avg/max =     28/29/32 ms

    #########################

    R3#show ip route
    Default gateway is 200.1.1.1

    Host               Gateway           Last Use    Total     Uses  Interface
    ICMP redirect cache is empty

    R3#ping 100.1.1.2
    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 100.1.1.2, timeout is 2     seconds:
    !!!!!
    Success rate is 100 percent (5/5), round-trip min/avg/max =     12/15/16 ms

    #########################

    R4#show ip route
    Default gateway is 200.1.1.1

    Host               Gateway           Last Use    Total     Uses  Interface
    ICMP redirect cache is empty

    R4#ping 100.1.1.2   
    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 100.1.1.2, timeout is 2     seconds:
    !!!!!
    Success rate is 100 percent (5/5), round-trip min/avg/max =     28/29/32 ms