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. Also, remember to sign up via the link in the description to get all of the lab files for this course, so you can try it out yourself in packet tracer. If you want more labs like these, I highly recommend picking up Boson’s NetSim for the CCNA, click the link in the video description to check it out. It’s a network simulator like packet tracer, but it’s even better, and it includes all of these guided labs to not only help you get hands-on practice configuring and troubleshooting, but also deepen your understanding of the exam topics. I used it myself when studying for my certifications, so I feel confident about recommending it to all of you. If you want to get your own copy of NetSim, please follow the link in the video description. In this lab we will configure DNS, Domain Name System. DNS is used to translate easy-to-remember names like youtube.com to IP addresses. We’ll configure R1 and these three PCs to use 1.1.1.1 as their DNS server. Unfortunately, the IP DNS SERVER command isn’t available in Packet Tracer, so we can’t configure R1 to act as a DNS server for the internal hosts. By the way, 1.1.1.1 is an actual DNS server provided by Cloudflare. In the lecture video I used 8.8.8.8, Google’s DNS server, but I wanted to introduce another public DNS provider. Of course, this is Packet Tracer, so this server isn’t a real server, but you can configure 1.1.1.1 as the DNS server on your PC if you want to actually use Cloudflare’s DNS server. Anyway let’s get started. In step 1 we will configure a default route to the Internet on R1. I thought about pre-configuring this, but it’s good to review the basics sometimes. So let’s go on R1. ENABLE. CONF T. And now I’ll configure the route. IP ROUTE 0.0.0.0 0.0.0.0, and then the next hop is 203.0.113.2. Let me point out that this INTERNET cloud is just a router, I just changed the icon. In the lab for day 1 of this course I did the same thing and I’ve gotten hundreds of questions about how to add the Internet cloud, so I just wanted to point that out. Now let me check that this default route is working. I’ll try to ping the Cloudflare DNS server at 1.1.1.1 DO PING 1.1.1.1. ARP can be slow in packet tracer so one or two pings might fail, but then R1 gets the response from the server. Okay now in step 2 I’ll configure PC1, PC2, and PC3 to use 1.1.1.1 as their DNS server. First I’ll go on PC1. From the config tab, you can configure the DNS server here under the default gateway. 1.1.1.1. Okay, that’s it. Now I’ll do the same on PC2. From the config tab, set the DNS server to 1.1.1.1. In the lecture video I mentioned that DHCP can be used to automatically learn things like the hosts IP address, default gateway, and DNS server. Notice here in packet tracer you can select either DHCP or static. We’ll use static for now, but I’ll cover DHCP soon in the course, maybe even the next video. Okay next PC3. From the config tab, set the DNS server to 1.1.1.1. Next in step 3 we’ll configure R1’s DNS server. We’ll also configure a host table on R1 for hosts in the local network, 192.168.0.0/24, so R1 will be able to ping them by name. I’ll return to R1. And let’s configure it to use 1.1.1.1 as well. IP NAME-SERVER 1.1.1.1. Then a host entry for R1 itself. IP HOST R1 192.168.0.254. Then for each PC, PC1 first. IP HOST PC1 192.168.0.1. Then PC2. IP HOST PC2 192.168.0.2. And then PC3. IP HOST PC3 192.168.0.3. Okay, that’s R1’s host table. I’ll check the host table with DO SHOW HOSTS. And there are the hosts we configured. I’ll try a ping to PC1 by name. DO PING PC1. And the ping is successful. R1 has an entry in its host table for PC1, so it is able to translate the name PC1 to 192.168.0.1. Note that the IP DOMAIN LOOKUP command must be enabled for R1 to do this, but it’s enabled by default so usually you don’t need to configure it. Finally in step 4 we will use Packet Tracer’s simulation mode to see the various messages that are sent when when PC1 pings youtube.com by name. Simulation mode is enabled here in the bottom right. Now I’ll go to PC1 and let’s do that ping. PING youtube.com. Okay, so there is a DNS query message here. Because R1 already pinged PC1, PC1 knows the MAC address of its default gateway R1, so PC1 doesn’t need to send an ARP request. The DNS message goes to R1, to the Internet, and to 1.1.1.1, before being sent back. Note that no ARP messages are needed here either. R1 already pinged 1.1.1.1 before, so the ARP process is already complete. Now that 1.1.1.1’s DNS response is back at PC1, let’s see the contents. From the ‘inbound PDU details’ tab, scroll down to the bottom and you can see the answer. Youtube.com’s IP address is 172.217.6.78. Notice PC1 has now created the ICMP message, the ping. If I click on it, you can see that the destination IP is 172.217.6.78, the IP address of youtube.com. The message goes to R1 and the Internet, but now the Internet router has to send an ARP message to youtube.com, because I haven’t sent any traffic between them yet in this lab. During that time PC1’s first ping fails, but then it sends another ping and it reaches youtube.com, and youtube.com replies. Okay, I’ll return to realtime mode now. If I go back to PC1, notice that the first ping failed, but the next three succeeded, because the ARP process in Packet Tracer is a bit slow. Simulation mode in Packet Tracer is a great tool to understand how traffic flows through a network. For PC1 to ping youtube.com, ICMP messages weren’t the only messages sent. DNS and ARP messages were needed too. There’s not much you need to know about DNS in terms of configuration, but make sure you understand its basic purpose and operations. Okay, that’s all for this lab. Now let’s take a look at a lab in Boson Software’s NetSim for CCNA. Okay here's today's Boson NetSim lab preview. The lab I have selected for today is Configuring DNS 1. Boson NetSim for CCNA has four DNS labs here. Configuring DNS 1 and 2, and then Troubleshooting DNS 1 and 2. So I've selected the first one. It has a pretty simple topology, one router, one switch and two PCs. Here are the commands you need to know. Some of these we covered in the lecture video. And some of these are NetSim specific commands, such as these ones here. IPCONFIG /DG to configure the default gateway, /IP to configure the IP address, and /DNS to configure the DNS server on a PC in NetSim. Okay here are the lab tasks. There are four tasks but for this little preview we'll just do task 1 and task 2. So let's get started with task 1, which involves configuring IP addresses on these devices. So first step 1. On Router1 configure the host name, enable the interface, and assign the appropriate IP address, okay. So here's Router1. I'll configure the host name. HOSTNAME Router1. And then here's the interface. INTERFACE F0/0. It's 10.0.0.1 /24. And I'll enable that. Okay I think that's it on R1. Next I'll go on to Switch1 and do the same. Okay now I'm going to configure an IP address on Switch1. This might be a new concept for you. Switch1 is a Layer2 switch but I'm going to configure an IP address on it. So, I will cover this in more detail when we cover SSH and Telnet in a later video, but Layer2 switches can have an IP address which you can use to connect to it to configure the switch, so you don't actually have to physically be next to the switch with a console cable. Anyway, I'll talk about that in a later video. So let's configure that IP address on the VLAN1 SVI, switch virtual interface. The IP address is 10.0.0.2 /24. And it should be enabled by default but I'll NO SHUT it just incase. Okay next, on the PCs, configure the appropriate IP address, subnet mask, and default gateway. Okay so now I'm going to use those NetSim-specific commands I showed you. First here on PC1. IPCONFIG /IP to set the IP address. 10.0.0.100, as it shows here. /24. And then to configure the default gateway its IPCONFIG /DG 10.0.0.1. And then I'll do the same on PC2. IPCONFIG /IP 10.0.0.101 /24. IPCONFIG /DG 10.0.0.1, okay. Next up, verify the IP address and subnet mask on Router1 and Switch1. Okay, DO SHOW IP INTERFACE BRIEF. Okay, on FastEthernet0/0, 10.0.0.1 and it's UP and UP. Now it says verify the IP address and subnet mask, but you can't actually view the subnet mask using SHOW IP INTERFACE BRIEF. So DO SHOW IP INTERFACE F0/0 will show us that. There it is, /24. Okay and I'll do the same on Switch1. DO SHOW IP INTERFACE BRIEF. VLAN1, 10.0.0.2, UP UP. But we can't see the subnet mask so I'll use DO SHOW IP INTERFACE, without the brief, VLAN 1. Okay, /24. Okay so we have verified the IP address and subnet masks on Router1 and Switch1. Finally, in step 5 we have to verify network connectivity by pinging to Switch1, PC1, and PC2 from Router1. Okay so let's do that. PING 10.0.0.2, that's Switch1, looks good. .100 is PC1, okay. And .101, PC2, great. Okay so that's task 1. We performed the initial configurations of host names and IP addresses and tested connectivity. Task 2 is to configure DNS. Okay from Switch1 ping Router1 by using the host name Router1 instead of Router1's IP address. Does the ping succeed or fail, and why? So, Switch1 doesn't have any DNS configurations yet so this should fail, let's see. PING Router1. And yes, unrecognized host or address. So Switch1 was unable to translate the host name Router1 to an IP address. Okay, and then step 2, on Router1 enable the DNS feature. Sorry, the DNS server feature, that's important. So IP DNS SERVER. So now Router1 will respond to DNS queries if it has the appropriate entry. And let's configure those entries here in step 3. Configure Router1 with two host table entries, Router1 and Switch1. Okay the command is IP HOST, 10.0., or sorry IP HOST, the hostname's first, and then the IP address., 10.0.0.1. And then for Switch1. Okay configure Switch1 to use Router1 as its DNS server and enable hostname-to-address translation. Okay, so to make Router1 its DNS server the command is IP NAME-SERVER and then the IP address. And to enable hostname-to-address translation, that is this command: IP DOMAIN-LOOKUP. Notice it's using the old version, with a hyphen. So, this command should be enabled by default, but it told us to enable it again anyway. Okay and then finally step 5. From Switch1 ping Router1 by using the name of the host instead of Router1's IP address to verify your configuration. So let's try that ping again and it should work this time. PING Router1. Okay, it says 'translating Router1' using domain server 10.0.0.1, which is Router1. And then it translates it to 10.0.0.1 and the pings succeed. Okay then if we were to go on to task 3 and 4, here we would edit a PC hosts file, remember I showed you in the lecture video what a PC hosts file is. And then we would configure DNS on PC1 and PC2. Okay so that's a quick look at Boson NetSim for CCNA. Boson NetSim has over 100 detailed labs like this, with a powerful network simulator. So it's a really fantastic study tool for the CCNA. If you're interested, you can check out Boson NetSim from the link in the video description. Before finishing today’s video I want to thank my JCNP-level channel members. To join, please click the ‘Join’ button under the video. Thank you to Tech Alameda, Marcel, Magrathea, Kone, Donald, C Mohd, Gustavo, Anthony, Biraj, Junhong, Njabulo, Benjamin, Tshepiso, Justin, Prakaash, Nasir, Erlison, Apogee, Marko, Daming, Jhilmar, Ed, Value, John, Funnydart, Velvijaykum, Mark, Yousif, Boson Software, Devin, Lito, Yonatan, and Vance. Sorry if I pronounced your name incorrectly, but thank you so much for your support. This is the list of JCNP-level members at the time of recording by the way, January 17th 2020. If you signed up recently and your name isn’t on here don’t worry, you’ll be in future videos. Thank you for watching. Please subscribe to the channel, like the video, leave a comment, and share the video with anyone else studying for the CCNA. If you want to leave a tip, check the links in the description. I'm also a Brave verified publisher and accept BAT, or Basic Attention Token, tips via the Brave browser. That's all for now.