Free CCNA | Troubleshooting Static Routes | Day 11 Lab 2 | CCNA 200-301 Complete Course

Summary

In this CCNA troubleshooting lab, Jeremy's IT Lab guides viewers through identifying and resolving network misconfigurations that prevent PC1 and PC2 from pinging each other. The video emphasizes the importance of hands-on practice for the CCNA exam, detailing the discovery and correction of errors on three routers. By the end, the network functions correctly, allowing successful pings, with a call to action for viewers to subscribe, engage, and support the channel.

Takeaways

• 😀 Welcome to Jeremy’s IT Lab, a free, complete course for CCNA aspirants.
• 📚 Encouragement to subscribe, like, comment, and share the video to support the free educational series.
• 🔍 Identification of a network topology with misconfigurations preventing PC1 and PC2 from pinging each other.
• 🛠️ Emphasis on troubleshooting as a critical skill for CCNA certification and its potential inclusion in the exam.
• 💡 Advice for viewers to attempt the lab independently to effectively practice troubleshooting skills.
• 🖥️ Demonstration of checking PC configuration using the 'IPCONFIG' command on Windows.
• 📡 Explanation of the 'physical address' being the MAC address, crucial for network interface identification.
• 🚀 Verification of the PC's ability to ping the default gateway, a prerequisite for accessing other networks.
• 🔍 On R1, the discovery of a misconfigured static route with the incorrect next hop address.
• 🛠️ Correction of the static route on R1 by changing the next hop address from 192.168.12.3 to 192.168.12.2.
• 🔄 On R2, the recognition of an incorrect exit interface in the static route configuration, leading to potential load-balancing issues.
• 🔧 Rectification of the exit interface on R2 from GigabitEthernet0/0 to GigabitEthernet0/1 for proper routing.
• 🔢 On R3, the identification of an incorrect IP address on the GigabitEthernet0/0 interface.
• 🔄 Immediate correction of R3's interface IP address without the need for prior deletion of the existing configuration.
• 📝 Brief inspection of R3's routing table to confirm the presence of a correct static route to the 192.168.1.0/24 network.
• 🔄 After fixing the misconfigurations, successful ping from PC1 to PC2 indicating resolution of the network issues.
• 👍 Final call to action for viewers to engage with the content and support the channel through subscriptions and sharing.

Q & A

What is the purpose of the video?

The purpose of the video is to provide a free, complete course for the CCNA certification, focusing on troubleshooting a network topology with misconfigurations.

What is the main issue presented in the lab?

The main issue is that PC1 and PC2 are unable to ping each other due to configuration errors on the routers.

Why is it important to try the lab before watching the video?

It is important to try the lab first to practice your own troubleshooting skills and to avoid already knowing the problems, which would reduce the learning experience.

What command can be used to check the configuration on a Windows PC?

The command 'IPCONFIG' can be used to check the basic configuration, and 'IPCONFIG /ALL' for more detailed information including the physical (MAC) address.

What is the significance of the default gateway in this context?

The default gateway is significant because it is the first point of contact for a PC to reach other networks, and it must be correctly configured for proper network communication.

What was the misconfiguration found on R1's routing table?

The misconfiguration was that the static route for the 192.168.3.0/24 network was pointing to the wrong next hop address, 192.168.12.3 instead of the correct 192.168.12.2.

How did the video demonstrate correcting the misconfiguration on R1?

The video showed entering global config mode, deleting the incorrect configuration statement, and then re-entering it with the correct next hop address.

What was the issue with R2's routing table?

The issue was that one of the static routes for the 192.168.3.0/24 network had an incorrect exit interface, GigabitEthernet0/0 instead of the correct GigabitEthernet0/1.

Why is it problematic to have two static routes for the same network in the routing table?

Having two static routes for the same network can lead to load-balancing, which might send packets out of incorrect interfaces, causing network communication issues.

What was the misconfiguration on R3's interface?

The misconfiguration was that R3's GigabitEthernet0/0 interface had an incorrect IP address, 192.168.23.3, instead of the correct 192.168.13.3.

How did the video ensure that the misconfigurations were fixed after making changes?

The video checked the routing table and interface configurations using commands like 'SHOW IP ROUTE' and 'SHOW RUNNING-CONFIG' to confirm that the changes were applied correctly.

What was the final step to verify the lab's success?

The final step was to go back to PC1 and try pinging PC2 again to ensure that the network was functioning correctly after the misconfigurations were fixed.

Outlines

00:00

😀 Introduction to CCNA Troubleshooting Lab

Jeremy’s IT Lab offers a free, comprehensive course for CCNA certification. The video script begins by inviting viewers to subscribe, like, comment, and share the content to support the free educational series. The lab scenario involves a familiar network topology with configuration errors that prevent PC1 and PC2 from pinging each other. The script emphasizes the importance of troubleshooting for the CCNA exam and encourages viewers to attempt the lab independently to practice their skills. The initial step is to confirm the communication issue between PCs, followed by a quick check of the PCs' IP configurations using the 'IPCONFIG' command. The script then moves on to router troubleshooting, starting with R1.

05:10

🛠️ Troubleshooting Router Configurations in a CCNA Lab

The script continues with a step-by-step guide to identify and fix configuration errors on three routers (R1, R2, and R3) within a network setup. For R1, the issue lies in a static route misconfiguration, where the next hop address is incorrect. The script demonstrates how to correct this by editing the routing table. Moving to R2, another static route problem is identified, where the exit interface for the 192.168.3.0/24 network is incorrect. The script shows how to remove the wrong route and add the correct one, preventing packet misrouting. Lastly, R3 has an interface IP address error, which is corrected by reconfiguring the interface with the right IP. After addressing these issues, the script concludes with a successful ping test between PC1 and PC2, indicating the network is now correctly configured. The video ends with a call to action for viewers to engage with the content and support the creator.

Keywords

💡CCNA

CCNA stands for Cisco Certified Network Associate, which is a foundational certification for network professionals. It validates the ability to install, configure, operate, and troubleshoot medium-sized routed and switched networks. In the video, the course is designed to prepare viewers for the CCNA exam, and the lab exercises are directly related to the skills tested in the certification.

💡Network Topology

Network topology refers to the arrangement of the network elements such as nodes, links, and the way they are connected. In the context of the video, the network topology is the layout of the network that has been configured in a previous lab, and the video focuses on troubleshooting issues within this specific topology.

💡Misconfiguration

A misconfiguration is an incorrect setup or setting in a network device that can lead to connectivity issues. The video script mentions that there are misconfigurations on the routers which prevent PC1 and PC2 from being able to ping each other, and the main task is to identify and correct these misconfigurations.

💡Troubleshooting

Troubleshooting is the process of identifying and resolving issues in a system. In the video, troubleshooting is a key activity where the presenter guides viewers through the process of finding and fixing network issues, which is a critical skill for the CCNA exam and real-world network administration.

💡IP Address

An IP address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. In the script, the IP address is used to identify the network interfaces and is crucial for the ping test and routing configurations.

💡Subnet Mask

A subnet mask is used to separate the network address from the host address within an IP address. In the video, the subnet mask is part of the PC's configuration that is checked to ensure proper network communication.

💡Default Gateway

The default gateway is the IP address of the router on a network that devices use to send data to other networks. In the script, the presenter verifies that PCs can ping their default gateway, which is a necessary step for reaching other networks.

💡MAC Address

A MAC address, also known as a physical address, is a unique identifier assigned to network interfaces for communications on the physical network segment. The script mentions the MAC address in the context of using the 'IPCONFIG /ALL' command to check for detailed network configuration information.

💡Routing Table

A routing table is a data file in a router or networking software that defines routes to particular network destinations. In the video, the presenter checks and corrects entries in the routing table to ensure proper network routing.

💡Static Route

A static route is a path that is manually configured on a router and does not change unless altered by a network administrator. The script describes a misconfigured static route that needs to be corrected for the network to function properly.

💡Load Balancing

Load balancing is the distribution of network or application traffic across multiple servers or network paths. In the video, the incorrect static route causes unintended load balancing, which is problematic because it leads to some packets being sent out the wrong interface.

💡Interface

In networking, an interface refers to a communication endpoint between a device and a network. The script discusses checking and correcting interface configurations, such as IP addresses, to ensure proper connectivity.

Highlights

Introduction to Jeremy’s IT Lab's free, complete CCNA course.

Encouragement for subscribers to engage with the content through likes, comments, and shares.

Identification of a network topology with configuration errors preventing PC1 and PC2 from pinging each other.

Emphasis on troubleshooting as a valuable practice for CCNA exam preparation.

Advice to attempt the lab independently before watching the solution video for effective learning.

Confirmation of the initial problem where PC1 cannot ping PC2.

Quick check of PC’s configuration using the IPCONFIG command.

Explanation of the physical address, which is the MAC address.

Verification of the default gateway's reachability from PC1.

Identification of a misconfiguration in R1's static route pointing to the incorrect next hop address.

Demonstration of how to correct a misconfiguration in the router's running configuration.

Fixing the incorrect exit interface in R2's routing table for the 192.168.3.0/24 network.

Clarification on the concept of load-balancing in routing and its implications in this scenario.

Identification and correction of R3's incorrect IP address on the GigabitEthernet0/0 interface.

Brief inspection of R3's routing table to confirm the presence of a static route to the 192.168.1.0/24 network.

Successful resolution of the network issues allowing PC1 to ping PC2 after corrections.

Call to action for viewers to subscribe, engage, and share the video for others studying for the CCNA.

Mention of accepting tips and providing links in the description for Brave verified publisher status.

Transcripts

Welcome to Jeremy’s IT Lab.

This is a free, complete course for the CCNA.

If you like these videos, please subscribe to follow along with the series.

Also, please like and leave a comment, and share the video to help spread this free series

of videos.

Thanks for your help.

You may recognize this network topology.

This is the same network we configured in the previous lab.

However, this time there are a few configuration errors, so PC1 and PC2 are unable to ping

each other.

As the lab instructions say, there is one misconfiguration per router, so we have to

find and fix the misconfigurations.

Troubleshooting labs like this are great practice for the CCNA.

Troubleshooting helps test your knowledge of the concepts, and troubleshooting questions

may also appear on the CCNA exam itself.

I highly recommend you try to complete this lab yourself first, if you watch the video

before you will already know what the problems in the network are and you won’t

practice your own troubleshooting skills.

Okay, before we get started troubleshooting, we should confirm the problem.

PC1 and PC2 should not be able to ping eachother.

I’ll go on PC1 and try to ping PC2.

Okay, let’s send that ping.

Ping 192.168.3.1.

Okay, the ping indeed does not work.

Although the misconfigurations are on the routers in this lab, let’s quickly check

the PC’s configuration.

To check the configuration on a windows PC, use the command IPCONFIG.

Here you can see the IP address, subnet mask, and default gateway.

If you want more detail, use the command IPCONFIG /ALL.

This gives more information, such as the physical address.

What is the physical address?

Well, it’s the MAC address.

Okay, let’s see if we can ping the default gateway, since to reach other networks we

need to be able to reach the default gateway.

PING 192.168.1.254.

Okay, no problems here.

Let’s go on R1 now and see if we can find the issue...enter privileged exec mode with

ENABLE.

First I’ll check if the interface configuration is okay.

SHOW IP INTERFACE BRIEF...the addresses are correct, and both interfaces are UP/UP, so

the interface configuration is fine.

Let’s check the routing table.

SHOW IP ROUTE...here’s the static route for the 192.168.3.0/24 network, but can you

see the misconfiguration?

It says via 192.168.12.3, but actually the next hop address should be 192.168.12.2, which

is the IP address of R2’s G0/0 interface.

Let’s check it in the running config.

Show running-config, and then I’m going to filter the output by using the PIPE symbol,

INCLUDE, and then ip route.

Here you can see the configuration statement.

I’m going to right click to copy it, and then go to global config mode.

CONFIGURE TERMINAL.

Now I’ll paste in the configuration statement, and use the keyboard shortcut CTRL+A to go to

the beginning of the line. Type NO, followed by a space, and then hit enter.

and that deletes the configuration statement.

Let’s check.

DO SHOW RUNNING-CONFIG, PIPE, INCLUDE IP ROUTE.

Okay, it’s gone.

Now I’ll paste in the configuration statement once more, and change this 3 to a 2.

I’ll use the up arrows to go back to the show running-config command, and now you can

see we have the correct configuration statement.

Let’s check the routing table one last time.

DO SHOW IP ROUTE.

Okay, there’s the correct route.

So, we have fixed the problem on R1.

Now let’s move on to R2. Enter privileged exec mode with ENABLE.

And let’s check the interface configuration.

SHOW IP INTERFACE BRIEF.

The IP addresses both are correct, and the interfaces are UP/UP, so no problems here.

Let’s check the routing table.

SHOW IP ROUTE.

We have two static routes as expected, 192.168.1.0/24 via 192.168.12.1 is correct. And

192.168.3.0/24, with an exit interface of gigabitethernet0/0, there’s our problem.

To reach the 192.168.3.0/24 network, R2 should use the gigabitethernet0/1 interface, not

0/0.

Let’s see what happens if I enter the correct route without removing the incorrect one.

CONFIGURE TERMINAL.

IP ROUTE 192.168.3.0 255.255.255.0 g0/1.

DO SHOW IP ROUTE.

Okay, you can see both routes are kept in the routing table, the second does not override

the first.

Because both are in the routing table, this means the router will ‘load-balance’ over

the two routes, sending some packets out of G0/0, and some packets out of G0/1.

Sometimes load-balancing is a good thing, but in this case the G0/0 interface is totally

wrong, so we should remove that configuration statement.

DO SHOW RUNNING-CONFIG, PIPE, INCLUDE IP ROUTE. Okay,

right click to copy, right click to paste. Hit CTRL-A to skip to the beginning of the line, and

type no.

Let’s see if the route was removed from the routing table.

DO SHOW IP ROUTE.

Okay, now we only have one route to 192.168.3.0/24, using the correct interface, G0/1.

Finally let’s look for the issue on R3. First enter privileged exec mode with ENABLE.

And once again I’ll check the interface configuration first.

SHOW IP INTERFACE BRIEF.

Both interfaces are UP/UP, however there is a misconfiguration here.

R3’s gigabitethernet0/0 interface should have an IP address of 192.168.13.3, not 192.168.23.3.

Let’s fix that.

CONFIGURE TERMINAL.

INTERFACE G0/0.

Now, unlike when configuring routes, we don’t have to remove the current configuration first.

If we enter a new IP address, it will overwrite the current IP address.

Let’s see the config before and after.

DO SHOW RUNNING-CONFIG. Okay, here’s the incorrect IP address.

Now let’s configure the correct IP address.

IP ADDRESS 192.168.13.3 255.255.255.0.

Let’s check the config again.

DO SHOW RUNNING-CONFIG. As you can see, the previous configuration was automatically

overwritten, we did not have to delete it.

Okay, since we are told there is one misconfiguration per router, we don’t have to check the routing

table, but let’s take a quick look anyway.

R3 should have a static route to the 192.168.1.0/24 network.

DO SHOW IP ROUTE. There it is, via 192.168.13.2, which is R2.

Now that we have fixed the misconfigurations, let’s go back on PC1 and try out that ping

again.

The first ping or two might fail, but after that they should all succeed.

Let’s give it a shot.

PING 192.168.3.1.

Okay, so after finding and fixing the misconfigurations on R1, R2, and R3, PC1 is now able to ping

PC2.

That’s all for this lab.

Thank you for watching.

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with anyone else studying for the CCNA.

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