Unable to Resolve a Hostname or Domain Name

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來自 Google 的課程

System Administration and IT Infrastructure Services

875 個評分

Google

System Administration and IT Infrastructure Services

875 個評分

課程 4（共 5 門，Specialization Google IT Support Professional Certificate）

This course will transition you from working on a single computer to a whole fleet. Systems administration is the field of IT that’s responsible for maintaining reliable computers systems in a multi-user environment. In this course, you’ll learn about the infrastructure services that keep all organizations, big and small, up and running. You’ll learn how to manage and configure servers, how to use industry tools to manage computers, user information, and user productivity. Finally, you’ll learn how to recover your organization’s IT infrastructure in the event of a disaster. By the end of this course you’ll be able to: - utilize best practices for choosing hardware, vendors, and services for your organization. - understand how the most common infrastructure services that keep an organization running work and how to manage infrastructure servers. - manage an organization’s computers and users using the directory services, Active Directory, and OpenLDAP. - choose and manage the tools that your organization will use. - backup your organization’s data and be able to recover your IT infrastructure in the case of a disaster. - utilize systems administration knowledge to plan improve processes for IT environments. Except as otherwise noted, the contents on this site are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

從本節課中

Network and Infrastructure Services

In the second week of this course, we'll learn about network and infrastructure services. We will cover what IT infrastructure services are and what their role is in system administration. We'll also learn about server operating systems, virtualization, network services, DNS for web services, and how to troubleshoot network services. By the end of this module, you will know the most common IT infrastructure services you'll encounter when handling system administration tasks.

Unable to Resolve a Hostname or Domain Name4:41

與講師見面

Google

There will be times when you're working in an IT support role and

you won't be able to resolve or get the IP address of a website name.

This particular problem could be tricky to identify when you see it.

You might just think that your network connection isn't working.

Let's go ahead and try to navigate Google.com from our web browser.

So let me get to my webrowser and navigate to Google.com.

It doesn't look we get to Google.com.

Let's go over some of the tools that we learned in our networking class

that can help.

First off, if you're unable to resolve a domain name,

check that your network connection is actually working.

You can do a quick check and ping a website that you know is available.

An oldie but goodie is to ping www.google.com.

It's pretty rare that Google would be down, although it can happen.

So let me go into my terminal and type in ping www.google.com.

Looks like we're getting responses.

Let's move on to isolating another problem, DNS.

To verify that your DNS server is giving you a correct address for google.com,

you can use nslookup.

Remember that nslookup gives us the name server of a host or domain name, so

let me go ahead and do that on my terminal.

From here, we can rule out if DNS isn't issued by verifying that the host name

points to a name server.

If we copy the IP address of the result and paste it into the web browser,

it should resolve the website name if DNS is working.

Let's go ahead and do that.

So I'm going to go ahead and copy the non-authoritative IP address.

Open my web browser

So I see that's working.

What's going on?

It looks like my DNS settings aren't working correctly.

Let's look at my ping results again.

So I'm going to go ahead to my terminal and ping www.google.com.

I see that it checks an IP address different from what I have here.

If I go to this IP address, it doesn't take me anywhere.

So I'm going to take this IP address, copy this.

Remember that when a DNS query is performed,

your computer first checks host file.

Now if I access my host file here, I can see that I have an entry for

www.google.com.

And it points to a fake IP address.

If I remove this line right here where it says 127.1.1.3

And save that configuration file, And then restart my browser,

If I type in www.google.com, there we go, we're there.

And the correct DNS setting should be applied to www.google.com.

There are some situations where DNS can be tricky to navigate,

since there can be many contributing factors.

But as with any troubleshooting scenario,

remember to keep isolating the problem down until you can get to a root cause.

With time and experience, you'll learn a lot more about DNS and

how to troubleshoot it in the real world.

We've covered a lot of information in this module.

You learned about all the overall services needed in an IT instructor.

On top of that, you learned about computer services like remote access and

virtualization that help make your organization work more effectively.

Your team of leaned about essential networking services like DNS and DHCP.

Along with the overall picture of what's needed to set up DNS for an organization,

and why you'd want to do that.

Now we're going to test you on all that learning.

And don't forget, you can always go back and

review the material again if you need to before you take the quiz.

In the next module, we're going to cover two of the other IT

infrastructure services, software and platform services.

I'll see you there.

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