Learn about key DNS record types and their purpose, as well as split-horizon DNS.
- [Instructor] In the Office 365 Provision Office course, we talked about how you can use a custom domain, for your Office 365 deployment. What's more, we looked at how DNS Records, for that custom domain, could be hosted on a DNS provider of your choosing, or, you could leverage the relationship Microsoft has with GoDaddy, and automate everything, automate, certainly, the hosting of DNS Records. This chapter will, largely, look at the DNS Records needed, so that clients, in your organization, are able to find your Office 365 services, when they are using Office 365, over the internet.
As you learned, in the Office 365 Overview Lesson, this is a service that is web based, so, if clients can't make the network connection, Office 365 services will be very limited. I'll start things off with a brief overview of DNS, and all of the records that come into play, when it comes to Office 365, and DNS. First of all, DNS is an acronym, it stands for Domain Name System. That last S is sometimes referred to as server, I'll explain that in just a moment, here.
But, it's basically speed dial, for the internet. In fact, I don't even like to use the word basically, it is speed dial. Computers use numbers, like an IP address, much like phones use numbers, like the phone number. But, humans use names, you dial Brian. Your computer, when you sit down, at the browser, you log into Microsoft.com, you go to that domain, and you browse some of the services in that domain, whether that service be a web server, or a mail server, and so on.
So, with that said, let's lay a little bit of ground work, here, for the rest of the chapter. Here are the records it will help you to have a passing familiarity with. First of all A, A is a host record. And, this is a pointer, this is the speed dial for a host, or a service. And what's a host, a host is a computer. It's a thing that lives on the internet, that can be reached by knowing its number. But, again, humans don't have to know the number, we just need to know the names of computers.
DNS is the service that resolves that name to a number, and the host record, or A record, really is the bulk of all of the records that are kept, throughout the Domain Name System. Another record it will help to be familiar with, is CNAME record. CNAME stands for Canonical Name, these are used for aliases, for addressing a computer by more than one name, in some cases.
Similar, in concept, is this kind of a record, a Pointer record. A Pointer record is used for pointing an IP address, to an alias domain. An MX record will become part of your arsenal, when you're administering Office 365, and this is a Mail Exchange, or, sometimes, a Mail Exchanger name. This simply identifies mail services. So, when a piece of mail gets sent to microsoft.com, where are the servers that are running a service that can deal with that piece of mail? The Mail Exchange records, in the Domain Name System, help keep track of those servers.
Some other kinds of records that you should be familiar with, or, at least be able to sight recognize, is this one, a Text record, a TXT record. This is just that, it's a record that is used to store additional information. And, so, there are some very specific instances of a Text record, stored in DNS, that we'll talk about, as we continue on. This one we won't talk much about, but, it is helpful to at least know what this record is, and what its purpose is.
This is an NS record, a Name Server record, it helps identify other Name Servers throughout the Domain Name System hierarchy. An SOA record is a Start of Authority, it helps identify those Name Servers that are authoritative, for a section of the DNS Name space. And, finally, I'll mention the SRV record, SRV stands for Service record, which helps find the server that runs a specific service on behalf of another domain.
So, this is a very important type of a record, especially when it comes to Office 365 implementation, and, as we go, this will become more and more clear. So, to help put this all together, think about the Microsoft domain. Within that domain, there might be several services, being offered. There might be web servers, and web services, mail servers, servers that need to be found, if you want to log into the Microsoft domain. And, in some cases, all of these services, within a domain, can be hosted on the same server.
So, lots of services can resolve to the very same IP address, and, conversely, one IP address can represent several physical servers that provide redundancy, in case one of them fails. That's the very nature of the Cloud based services provided by Office 365. I know what you're thinking, what will they think up next? So, as I've mentioned before, for a broader understanding of DNS, I encourage you to search DNS, in the Course Library.
You'll find lots of great resources there. In fact, one of the very cool things about using a search, with our Course Library, is that the results will show you specific videos, alongside entire courses. So, usually, depending on the topic you're looking for, you can easily find a six minute, an eight minute video of specific training, on a subject, rather than have to sit through six hours, of an entire course. And, that's exactly the case, if you're looking for the topic of DNS, you can kind of search, independently, of what course it falls under.
So, if that helps you lay the foundation for continuing in this course, fantastic, great, use that resource. If not, we'll press on.
This course is ideal for any network administrator working with Office 365 and will serve as a valuable prep course for administrators wishing to learn the skills necessary to pass the exam.
- Configuring DNS records
- Registering DNS domains
- Configuring firewall ports
- Enabling Internet connectivity
- Administering Azure Rights Management
- Managing user roles