1.3.3 Packet Tracer – Troubleshooting a Small Network Answers
Topology
Addressing Table
| Device | Interface | IP Address | Subnet Mask | Default Gateway |
|---|---|---|---|---|
| Router1 | Fa0/0 | 172.16.30.254 | 255.255.255.0 | N/A |
| Fa0/1 | 172.16.31.126 | 255.255.255.128 | N/A | |
| Host1 | NIC | 172.16.30.1 | 255.255.255.0 | 172.16.30.254 |
| Host2 | NIC | 172.16.31.1 | 255.255.255.128 | 172.16.31.126 |
Learning Objectives
- Examine the logical LAN topology
- Troubleshoot network connections
Introduction
The configuration contains design and configuration errors that conflict with stated requirements and prevent end-to-end communication. You will troubleshoot the connectivity problems to determine where the errors are occurring and correct them using the appropriate commands. When all errors have been corrected, each host should be able to communicate with all other configured network elements and with the other host.
Task 1: Examine the Logical LAN Topology
Step 1. Design an IP addressing scheme.
The IP address block of 172.16.30.0 /23 is subnetted to meet the following requirements:
| Subnet | Number of Hosts |
|---|---|
| Subnet A | 174 |
| Subnet B | 60 |
Additional requirements and specifications:
- The 0 subnet is used.
- The smallest possible number of subnets that satisfy the requirements for hosts should be used, keeping the largest possible block in reserve for future use.
- Assign the first usable subnet to Subnet A.
- Host computers use the first IP address in the subnet.
- The network router uses the last network host address.
Based on these requirements, the following addressing requirements have been provided to you:
| Subnet A | |
|---|---|
| IP mask (decimal) | 255.255.255.0 |
| IP address | 172.16.30.0 |
| First IP host address | 172.16.30.1 |
| Last IP host address | 172.16.30.254 |
| Subnet B | |
|---|---|
| IP mask (decimal) | 255.255.255.128 |
| IP address | 172.16.31.0 |
| First IP host address | 172.16.31.1 |
| Last IP host address | 172.16.31.126 |
Examine each of the values in the tables above and verify that this topology meets all requirements and specifications. Are any of the given values incorrect?
If yes, make note of the corrected values.
Task 2: Troubleshoot Network Connections
Step 1. Begin troubleshooting at the host connected to the BRANCH router.
From host PC1, is it possible to ping PC2?
From host PC1, is it possible to ping the router fa0/1 interface?
From host PC1, is it possible to ping the default gateway?
From host PC1, is it possible to ping itself?
Where is the most logical place to begin troubleshooting the PC1 connection problems?
Step 2. Examine the router to find possible configuration errors.
Begin by viewing the summary of status information for each interface on the router.
Are there any problems with the status of the interfaces?
If there are problems with the status of the interfaces, record any commands that are necessary to correct the configuration errors.
Step 3. Use the necessary commands to correct the router configuration.
Step 4. View a summary of the status information.
If any changes were made to the configuration in the previous step, view the summary of the status information for the router interfaces.
Does the information in the interface status summary indicate any configuration errors on Router1?
If the answer is yes, troubleshoot the interface status of the interfaces.
Has connectivity been restored?
Step 5. Verify the logical configuration.
Examine the full status of Fa 0/0 and 0/1. Is the IP addresses and subnet mask information in the interface status consistent with the configuration table?
If there are differences between the configuration table and the router interface configuration, record any commands that are necessary to correct the router configuration.
Has connectivity been restored?
Why is it useful for a host to ping its own address?
