This one down here took 82 milliseconds on average to

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73. This one down here took 82 milliseconds on average to respond. By doing this we have built a map of hops between this system where traceroute is being run and this web server out on the internet. Summary 11:40-11:46 That's it for this demonstration. In this demo, we looked at two very useful troubleshooting utilities.We first looked at the ping command and then we looked at the traceroute command. Using nslookup 0:00-0:33 In this demonstration, we're going to spend some time working with the nslookup command.Nslookup is a useful network troubleshooting tool. Basically you use it to make sure that your name resolution service on your Windows or Linux system is working properly. Now it is a command. It has to be run from the command prompt. Therefore we're going to come down here to the Windows icon, right click and open up a command prompt session. Now nslookup can be used in one of two difficult modes. It can either be used in interactive mode or it can be used in non-interactive mode. Non-Interactive Mode 0:34-4:25 Let's take a look at non-interactive mode first. To run nslookup in non-interactive mode, I type 'nslookup' at the command prompt and then a space,followed by the DNS name that we want to resolve into an IP address. For example,www.testout.com. When I run this command, nslookup will take this DNS name and submit it to whatever
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DNS server this Windows system has been configured to use and say hey, please resolve this DNS name into an IP address for me and then the DNS server will do so and return the appropriate IP address to nslookup, which will then display it on the screen. Now let's go down here and open up a second command prompt window. And let's run the IP config/all command and we can see the DNS server that this system's been configured to use. Here you can see that the DNS server for this system has an IP address of 10.0.0.1 so when nslookup needs to resolve this DNS name into an IP address, it will send the request to the DNS server with an IP address of 10.0.0.1. Let's test it and see how it works. Here you can see that the request was sent to 10.0.0.1. Here's the DNS name that was sent to the DNS server and here's the response, 67.192.129.239. Now by running this command, we've learned a couple of things about our name resolution system.First of all, we've learned that this DNS server is up and running and that it's responding to requestsand also that it was able to resolve this DNS name into an IP address so we know that the DNS server itself is functioning the way it should so we know that the DNS configuration on the workstation is working properly and the DNS server itself is working properly. Now before we move on to interactive mode, I want to spend a minute looking at the response itself.Notice that this is listed as a non-authoritative answer. Why is it listed as a non-authoritative answer?Well this DNS server happens to be sitting about five feet away from me in this office where I am recording. It is a DNS server that I set up, therefore this DNS server is not authoritative for the testout.com domain, meaning that it doesn't have
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