4.4.8 Packet Tracer - Troubleshoot Inter-VLAN Routing Answers
Topology
Addressing Table
| Device | Interface | IP Address | Subnet Mask | Default Gateway | VLAN |
|---|---|---|---|---|---|
| R1 | G0/1.10 | 172.17.10.1 | 255.255.255.0 | N/A | VLAN 10 |
| G0/1.30 | 172.17.30.1 | 255.255.255.0 | N/A | VLAN 30 | |
| PC1 | NIC | 172.17.10.10 | 255.255.255.0 | 172.17.10.1 | VLAN 10 |
| PC3 | NIC | 172.17.30.10 | 255.255.255.0 | 172.17.30.1 | VLAN 30 |
Objectives
- Part 1: Locate Network Problems
- Part 2: Implement the Solution
- Part 3: Verify Network Connectivity
Scenario
In this activity, you will troubleshoot connectivity problems caused by improper configurations related to VLANs and inter-VLAN routing.
Instructions
Part 1: Locate the Network Problems
Examine the network and locate the source of any connectivity issues.
Commands you may find useful include:
R1# show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 unassigned YES unset administratively down down
GigabitEthernet0/1 unassigned YES unset up up
GigabitEthernet0/1.10 172.17.10.1 YES manual administratively down down
GigabitEthernet0/1.30 172.17.30.1 YES manual up up
Vlan1 unassigned YES unset administratively down downR1# show interfaces gigabitethernet 0/1.10 GigabitEthernet0/1.10 is administratively down, line protocol is down (disabled) Hardware is PQUICC_FEC, address is 000d.bde7.0c02 (bia 000d.bde7.0c02) Internet address is 172.17.10.1/24 MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation 802.1Q Virtual LAN, Vlan ID 30 ARP type: ARPA, ARP Timeout 04:00:00, Last clearing of "show interface" counters never
R1# show interfaces gigabitethernet 0/1.30 GigabitEthernet0/1.30 is up, line protocol is up (connected) Hardware is PQUICC_FEC, address is 000d.bde7.0c02 (bia 000d.bde7.0c02) Internet address is 172.17.30.1/24 MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation 802.1Q Virtual LAN, Vlan ID 10 ARP type: ARPA, ARP Timeout 04:00:00, Last clearing of "show interface" counters never
S1# show interfaces trunk S1#
- Test connectivity and use the necessary show commands to verify configurations.
- Verify that all configured settings match the requirements shown in the Addressing Table.
- List all of the problems and possible solutions in the Documentation Table.
Documentation Table
| Problems | Solutions |
|---|---|
| The G0/1 physical interface is up but G0/1.10 subinterface is administratively down. | Implement the no shutdown command to enable the G0/1.10 subinterface. |
| PC3 is configured with the wrong default gateway address. | Change the default gateway on PC3 from 172.17.10.1 to 172.17.30.1. |
| Interface G0/1 on S1 is configured as an access port instead of trunk port. | Use the command switchport mode trunk to change the interface from access mode to trunk mode. |
| Subinterface VLAN assignments are switched on R1. The configured assignments do not match the ones shown in the Addressing Table. | Issue the no encapsulation dot1q command to remove the incorrect configuration. Then configure the subinterfaces with the correct encapsulation dot1q vlan_number command. Re-enter the correct IP address information. |
Part 2: Implement the Solutions
Implement your recommended solutions.
Problem 1: Enable the G0/1.10 subinterface on R1.
R1(config)# interface gigabitethernet 0/1.10 R1(config-subif)# no shutdown
Problem 2: Change the default gateway on PC3 from 172.17.10.1 to 172.17.30.1.
Problem 3: Configure G0/1 on S1 as a trunk port.
S1(config)# interface gigabitethernet 0/1 S1(config-if)# switchport mode trunk
Problem 4: Correct the swapped subinterface VLAN assignments on R1. Remove the encapsulation from both subinterfaces first; otherwise IOS rejects the new VLAN ID because it is still in use on the other subinterface.
R1(config)# interface gigabitethernet 0/1.10 R1(config-subif)# no encapsulation dot1Q R1(config-subif)# interface gigabitethernet 0/1.30 R1(config-subif)# no encapsulation dot1Q R1(config-subif)# interface gigabitethernet 0/1.10 R1(config-subif)# encapsulation dot1Q 10 R1(config-subif)# ip address 172.17.10.1 255.255.255.0 R1(config-subif)# interface gigabitethernet 0/1.30 R1(config-subif)# encapsulation dot1Q 30 R1(config-subif)# ip address 172.17.30.1 255.255.255.0
Part 3: Verify Network Connectivity
Verify the PCs can ping each other and R1. If not, continue to troubleshoot until the pings are successful.
C:\> ping 172.17.10.1 C:\> ping 172.17.30.10
C:\> ping 172.17.30.1 C:\> ping 172.17.10.10
Device Configs - Final
ROUTER R1
! ============================================================== !--- 4.4.8 Packet Tracer - Troubleshoot Inter-VLAN Routing !--- FIX SCRIPT FOR ROUTER R1 !--- Usage: copy this whole file and paste it into the R1 terminal (start at the R1> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless. !--- Troubleshooting lab: only the corrective commands from the Documentation Table. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Problem 4: subinterface VLAN assignments are swapped. ! -------------------------------------------------------------- !--- Remove the wrong 802.1Q tag from BOTH subinterfaces first - a VLAN ID cannot be applied while the other subinterface still uses it. interface gigabitethernet 0/1.10 no encapsulation dot1Q exit interface gigabitethernet 0/1.30 no encapsulation dot1Q exit !--- Apply the correct VLAN and re-enter the IP address (removing the encapsulation also removes the address). interface gigabitethernet 0/1.10 encapsulation dot1Q 10 ip address 172.17.10.1 255.255.255.0 exit interface gigabitethernet 0/1.30 encapsulation dot1Q 30 ip address 172.17.30.1 255.255.255.0 exit ! -------------------------------------------------------------- !--- Problem 1: G0/1.10 is administratively down. ! -------------------------------------------------------------- interface gigabitethernet 0/1.10 no shutdown exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show ip interface brief -> G0/1, G0/1.10, G0/1.30 up/up !--- show interfaces gigabitethernet 0/1.10 -> 802.1Q VLAN ID 10 !--- show interfaces gigabitethernet 0/1.30 -> 802.1Q VLAN ID 30 ! ==============================================================
SWITCH S1
! ============================================================== !--- 4.4.8 Packet Tracer - Troubleshoot Inter-VLAN Routing !--- FIX SCRIPT FOR SWITCH S1 !--- Usage: copy this whole file and paste it into the S1 terminal (start at the S1> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless. !--- Troubleshooting lab: only the corrective commands from the Documentation Table. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Problem 3: G0/1 (to R1) is an access port instead of a trunk. ! -------------------------------------------------------------- interface gigabitethernet 0/1 switchport mode trunk exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show interfaces trunk -> Gig0/1 on, trunking, VLANs 10 and 30 active !--- From PC1: ping 172.17.30.10 (PC3) -> successful ! ==============================================================
PC3
PC3PC
IP Address172.17.30.10
Subnet Mask255.255.255.0
Default Gateway172.17.30.1
Command Promptipconfig 172.17.30.10 255.255.255.0 172.17.30.1
