Troubleshooting IP, IPv6 and Static Routing #1

Background Information:  The Accounting department is using a single router to route between two subnetworks that contain their user LAN and their server.  A network administrator has configured the router’s interfaces, but the users on the Accounting LAN are reporting that they cannot connect to the accounting server, which is located on the 10.0.0.0/24 network and has the IP address of 10.0.0.12.  The users on the Accounting LAN are still able to connect to each other.  No other issues have been reported to the help desk.

Task:  The network administrator has provided you with the following topology, but he did not document which interfaces he connected on the router.  Given the topology and the show command output below, identify the two configuration errors on the router that are preventing server connectivity for the users on the Accounting LAN.

AccountingGateway#show running-config
Building configuration…
Current configuration : 722 bytes
!
version 15.1
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname AccountingGateway
!
ip cef
no ipv6 cef
!
spanning-tree mode pvst
!
interface GigabitEthernet0/0
no ip address
duplex auto
speed auto
shutdown
!
interface GigabitEthernet0/1
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto
shutdown
!
interface GigabitEthernet0/2
ip address 10.0.0.1 255.255.255.252
duplex auto
speed auto
!
interface Vlan1
no ip address
shutdown
!
end

Hint

Router interfaces.

Answer

We have a limited amount of information to work from in this exercise; however, we can verify that we are viewing the running configuration for the AccountingGateway router based on the command issued and the hostname entry in the output. Even though the topology doesn’t define the specific interfaces on the router that are being used to serve the two LANs, we can determine, based on the show running-config output, that they are interfaces G0/1 and G0/2 (specifically, interface G0/1 is the gateway for the Accounting LAN with the IP address of 192.168.1.1, and interface G0/2 is serving the server network with a gateway IP address of 10.0.0.1).  Based on the configuration output, interface G0/1 apparently has not been issued the no shutdown command to have been moved into an up state, and interface G0/2 has a subnet mask of 255.255.255.252, which is a /30 network, yet the topology specifically documents that the server LAN is a /24 network.  The show ip interface command could also verify the interface issues shown here.