 There are my slides with everyone. So you can click on the links in that. Let me drop the link in the Zoom chat. There are slides. There we go. And so under my victory, that's a link to my Twitter account. If you have any questions or anything after the session, you can contact me there as well. So I just mentioned the WordPress training team. So I wanted to give a brief introduction about the team before we jump into today's content. The WordPress training team, we create resources and maintain the website called Learn WordPress. So if you go to learn.wordpress.org, this is the official WordPress educational website. It only started a year or two ago, so we're still in the process of getting it set up and there's a design change happening right now. But our goal is to become the first place people go to learn about WordPress. And the topic I'm about to talk to you today, I've already hosted once as part of the Learn WordPress website. So what is the domain name system? I did this a bit earlier in the year. Mayank reached out to me and said it would be a good topic for the meetup group here. And so I've brought the same presentation, pretty much the same, and I'm excited to share it with everybody here. All right. So before we jump in, I do want to ask everybody a question. So please enter your answer into the Zoom chat here. How familiar are you with the domain name system? So from a scale of one to five, one is I've never heard of it. Today's my very first time hearing about the DNS. All the way to number five, I consider myself an expert. So on that scale of one to five, where do you see yourself? You have a three from Archish, three from Mayank, three from Baibab, three, okay, we have a lot of threes, which is good. Anybody else? I'll presume everyone's pretty much a three then. So you probably have heard a bit about it and you're wanting to learn a bit more today, which is great. Now, I consider myself maybe a four. I'm definitely not an expert. So if there's something I say and if anybody else has additional information they want to share, feel free to jump in and share that with everyone too. All right, so domains, what are domains? Just starting from a bit of the basics, some of the most well-known domains in the world include Google.com, YouTube.com, Facebook.com, Twitter.com, Instagram.com. These are actually the top five most accessed websites in the world. And probably I presume a lot of people here have accessed a couple of these in the past as well. Google.com I access pretty much every day. YouTube.com I access pretty much every day as well I think. And then we have Facebook, Twitter and Instagram which are all very familiar social networking services. We also have Baidu.com, which is the Chinese search engine. We have Wikipedia.org, Yahoo.com, WhatsApp.com and as a bonus, I've also added WordPress.org. So WordPress.org is the main website for the WordPress project and where you can also download WordPress into your computer or server. So we'll be using WordPress.org as an example today as we look at the domain name system. All right, so the internet is a complicated network of devices. So of course our computers are connected, our phones are connected, we have servers, we have routers, but now you also have household appliances like refrigerators and washing machines and lights and doorbells and all these things are connected to the internet. And the internet is where these machines talk to each other. So for example, this computer in the middle says, I'm trying to find the WordPress website and it connects to the blue server and the blue server says, sure the server over there has the information. And so the computer connects to the orange server and says, hi, I'm trying to find the WordPress website and the orange services. I have the data, let me send you the website and your computer says, thanks. And so there's a lot of back and forth that goes on the internet with devices talking to each other. When they talk to each other, devices need a name they can call each other by just like you and I have a name so people can call us with our names. All the devices on the internet also have a name. These names are numbers, computers like numbers, computers like to calculate numbers. So every device on the internet has a number which is the equivalent of their name. So again, in this example, the computer says, I'm trying to find the WordPress website and the blue server says, sure, it's on server 1.98.143.164.252. Now, if you wanted, you could copy this number which is called an IP address. You could copy that number and paste it into your browser, oops, paste it into your browser, and that number will take you to the WordPress website. With IP version four, you can type IP addresses into your web browser and access many websites. So that's the number of the WordPress.org server. But the problem is humans don't like numbers, computers like numbers, but humans don't. So for example, when I want to search for something, I need to access 142.250.72.110. So that number, let's have a look. That number is the number for Google.com. Or for example, when I want to log into Facebook, I go to 157.241.35. So you get the idea. If we wanted to, we could remember these numbers for all the websites we visit and access the numbers directly. But that is confusing and we're just not really good with numbers. And this is IP version four. IP version six, the new IP address system, the numbers are a lot longer. And so they're a lot more complicated for humans to remember. So what we decided to do was we would create names to help us remember the numbers better. So rather than accessing 142.250.72.110, instead we access Google.com because that's a lot easier to remember. Or we go to Facebook.com, WordPress.org. And if it's your own blog, coolname.log. Humans can remember these four names easier than four sets of numbers. And this is exactly what the domain name system is. So the domain name system is the correlation between numbers and domain names. So somebody decided to call 198.143.164.252 WordPress.org. Somebody decided that 20 years ago. And so they're using the domain name system to map one name to one number. And the same thing for Google.com. So that is an overview of what the domain name system is. It's the process of mapping numbers to names, domain names. And today we're going to go into more detail about how exactly that happens. So today's content, first of all, we'll talk about what the domain name system is and how it works. We're gonna look at some DNS records. We're gonna talk about where you can edit your DNS records, what DNS records you need for your site. And finally, domain record propagation. So when we talk about DNS, propagation is another word that comes up often. So we'll have a quick look at what that's about. Let me pause there quickly. Does anybody have any questions so far? Are we ready to jump in? Anthony, you're ready to jump in? Great. Cool. So at the end of each of these sections, I will pause and have a look at the questions in the Zoom chat. So feel free to put the questions in while I'm talking and I will get to them at the end of each of these sections. All right, so let's move on. How does the domain name system work? So it's the process of converting numbers to domain names, but how exactly does that conversion work? So let's break that down a bit further. Before we jump into that, for those who aren't familiar, I just want to do a refresher of what the different parts of the domain are called. So when you look at a domain, different sections are divided by dots or periods. The section at the far right here is called the top level domain or the TLD. And then the next section here is called the second level domain. And then you have third level domain, fourth level domain, fifth level domain, et cetera. So you can have as many domains go down to the left, but the section on the far right is called the top level domain. The top level domain is the most general part of the domain. And the further left you go down, the more specific it becomes. So in this example, we know .org is a domain name often used for organizations. So we know this domain is probably for an organization. Then the second part says WordPress. The second level domain says WordPress. So this domain WordPress.org is probably for the WordPress organization. And then if we look at the third level domain, it says make. So make.wordpress.org gives us an idea. This is probably something about making WordPress. And if we go to make.wordpress.org, you'll see it talks about whether you're a budding developer, designer, or just like helping out, we're always looking for people to help make WordPress even better. So this is actually the landing page for all the community members who contribute to make WordPress. And we could guess that by looking at the domain name. So you have top level domain, the second level domain, third level domain, et cetera. And then you have the third level domain. All right. This is how a DNS look up works. Now you don't have to re-throw all of that. Right now I'm gonna go through step by step. But this is just to give you an overview. So you know, whenever you look for a domain name, before you see the site, there are all these different servers involved. So let me explain those one at a time. All right. So you're on your computer and you type WordPress.org and press Enter. What happens after that? Well, first of all, your computer doesn't know where WordPress.org is. It doesn't know where that server lives. And so what your computer does is it connects to a DNS resolver. So there are a number of DNS resolvers in the world and the job of the DNS resolver is to turn the domain name into an IP address. So what your computer does is it says DNS resolver. I'm looking for the IP address for WordPress.org. You go and find what it is and when to get the answer, come back and let me know. So the DNS resolvers is sure. Now the DNS resolver has a list in itself of DNS root name servers. So there are about a dozen DNS root name servers in the world and these DNS root name servers have a record of where all, oops, have a record of where all the top level domain name servers exist. So we have a look before it domains and we looked at the top level domain. In our example, it was .org but there are lots of other top level domains in the world. We have like .com or .info, .beers, .net, .xyz. And then you also have like country codes, top level domains, .id, .jp, .au, et cetera. For each of these top level domains, there is only one top level domain name server in the world. So for example, there is only one top level domain server for .org in the entire world. There is only one top level domain name server for .com in the entire world. So the job of the DNS root name server is to record where all these top level domain name servers exist. So the DNS resolver, so your computer says, I'm looking for the IP address for WordPress.org. The first thing the DNS resolver says, it connected the DNS root name server and says, I'm looking for the IP address for WordPress.org and the root name server says, go to this IP address, which is the top level domain name server for .org. So the root name server still doesn't know where the WordPress.org website lives, but it knows where the .org top level domain name server lives. And so it gives that IP address to the DNS resolver. All right, so the DNS resolver now knows where all the .org domains are registered. So it goes to the .org TLD name server and says, I'm looking for WordPress.org. Now the top level domain name server, it doesn't know where WordPress.org lives. It doesn't know the IP address, but it does know who the authoritative name servers for WordPress.org are. So we have a new type of DNS server here called authoritative nameservers for WordPress.org. Authoritative nameservers is where you register your DNS records. So when you purchase a domain and you set up your DNS records and you type them in, you're typing them in to a authoritative name server. And then your authoritative name server behind the scenes connects to the TLD name server and says, I have all the records for the WordPress.org domain. If anybody ever comes to you asking for the records, please contact me. So the authoritative name server holds all the records and just lets the TLD name server know, I am the authoritative name server, please come to me if anybody ever asks you about the WordPress.org domain. So the TLD name server tells the DNS resolver the IP address for the authoritative name server for WordPress.org. So the DNS resolver has already connected to the root name server. It's now connected to the TLD name server. And a third one, it finally connects to the authoritative name server for WordPress.org. So it connects to the authoritative name server, says, I'm looking for WordPress.org. The authoritative name server says, sure, the IP address for WordPress.org is 198.143.164.252. So finally, after three tries, the DNS resolver has finally got the IP address. So it sends that back to the computer. Initially, the computer said, it's looking for WordPress.org. It doesn't know all this has gone on behind the scenes. The DNS resolver has done that secretly. And so it just gives the answer, 198.143.164.252. So the computer now connects to that IP address. So it knows this one. It is the web server for the WordPress.org site. So it connects to this server and says, please send me the site data for WordPress.org. So the web server says, sure, here's the site data for WordPress.org. That comes back. And then the computer shows the site to us in a browser. So before when I opened the site, so I went to wordpress.org and like, oops, that one doesn't exist, wordpress.org, and in like a second, the site is shown. But behind the scene, all this was actually going on before the site was shown to us. Our computer connected to a DNS resolver. The DNS resolver connected to three other DNS servers. It gave the answer back. My computer finally connected to the web server. The web server data came back and it showed the site. All of this happens within a second. So that is sort of the details of how a DNS lookup works. The process of translating a domain name into an IP address. So just to refresh, DNS is the relationship between domain names and resources on the internet. DNS servers translate domain names to IP addresses for you. All right, so Bijoy has a question here. Is it possible to see these network calls to root, TLD and authoritative name servers? So you're probably wanting to look at these here. So from the DNS resolver. Hmm. If you had access, I'm pretty sure you can. I'm pretty sure there's like a terminal command you can run to see how it goes through all of those. I would have to look it up though. But if you, I'm pretty sure there is a way to look up this process. Ask Google. I think you've asked Google, it'll give you the answer. But I'm pretty sure the answer is yes. Sure, thanks. Yep. Any other questions before we move on? All right. So what are DNS records? So we talked before how all the DNS records are saved in the authoritative name server. But what exactly are DNS records? So DNS records are text files that give information about the domain. They are just text files. So text files are like the smallest file that exists on the internet almost. They live on your authoritative name servers and you can use tools like Google's dig app to look up DNS records. So we're going to be using this today. So I'll open that up. I will drop the link in the Zoom chat here for people who want this link too. So what this tool does is you can type in any domain at the top here, wordpress.org, hit Enter, and then you can click on all these domain name record types and it will give you the information about that domain record. So the reason why I know the IP address for wordpress.org is because I asked this tool, the Google admin tool box dig tool. So the wordpress.org A record has a TTL value of seven minutes and eight seconds and the data for this record is 198.143.164.253. And if you have a look at the different records, you'll see some of these records exist, but some of them don't. So the AAA record doesn't exist. The CNAME record doesn't exist. Let's see MX records, I'm pretty sure. Yep, the MX records exist. And this records exist. And then TXT records exist as well. Some of these other ones here, I don't think exist. So you can see, you don't have to set every domain record type. You just have to set the ones you need. And we can make the changes to these records. So domain owners can log into their authoritative name servers and change the domain name records. So just to refresh, domain name records are stored here. Okay, now, when looking at this over here, we mentioned, we saw there was a TTL value. So what is the TTL value? TTL stands for time to live. And this tells the device how long to remember the record before coming back to ask for the same information. So it tells DNS servers, this record, for example, has a time to live value of seven minutes. So for seven minutes, it's not gonna change. For seven minutes, you can keep that record. You don't have to keep coming back and asking me. And you can remember that number, that domain record for seven minutes, and it should work. And so temporarily saving information like this is called caching. And so in the domain name system, caching happens in a lot of places. So we looked at how our computer connects to a DNS resolver and then that connects to different lots of servers here. But when does this time to live value really make sense? So for example, if you're browsing a website, sometimes you accidentally close your browser and something happens and you go, ah, I closed my browser, I need to open that page up again. So you open the page up, you type in wordpress.org, your computer says, connects to DNS resolver and says, hi, I'm looking for the IP address for wordpress.org. And the DNS resolver goes, hang on just a moment. I just looked up this DNS record two minutes ago. And it looks at its history and the history says the record it received before has a four hour time to live value. So that means for four hours, I don't actually have to go searching for that again. I can just send the same information back. And then the DNS resolver skips connecting to all these DNS servers and instead just send the information it has already stored in itself back to the computer. So this is good in a few ways. First of all, it saves times because every time you have to make a call to a server, that takes time. So by having a time to live value, the DNS resolver is able to quickly process information better. The other thing is the internet like lines have an infinite, sorry, they have a limited number of calls they can process in a second. So usually at nighttime, the internet lines get busy and your internet speed drops by using TTL values, caching and if the DNS resolver doesn't have to make all these calls, then that frees up that much space on the internet lines for other people to use it for other things. So it makes things quicker, it also frees up internet bandwidth and TTL values have different benefits like that. All right, so common types of DNS records. If you open the Wikipedia page for DNS records, you'll see there are at least 48 types of DNS records. So Google's dig tool gave us two, four, six, eight, 10, two, four, 15 records, but that's actually just a third. If you wanted to add more records, you could add at least 48 types of domain records. But practically, you'll probably never need all 48. If you're running a business website, then you'll probably need somewhere between five to eight types of domain name records. You'll rarely ever need all 48. So today we're just gonna have a look at the five most used domain name record types, which are A, C name, TXT, MX and NS records. All right, so the most common type of domain records is the A record. And the A record is basically the IP address of a website. So if you were to access that domain and you're looking for the website information, the A record has the IP address of the web server where the website is stored. So in this case with WordPress.org, the A record says the data is at 198.143.164.2.3. So we know the website data for this domain is stored on this web server. So an A record is pretty simple. It's just an IP address and a time to live value. And time to live values are listed in seconds. And I think the maximum is about four hours. So if you have a website, your website's domain will definitely have an A record. For example, my personal log is called the sun's log. If you look that up, you'll see it has two A records. Both of them are time to live value of one hour and 199.164.172.143. So this is my web host IP address. All right, the second type of DNS record is CNAME records. CNAME records forward one domain to another domain. So an example is before we were talking about make.wordpress.org. So make.wordpress.org. So you'll see this has a third level domain. So this is a sub-domain of the WordPress.org domain. WordPress.org is the parent domain. Make.wordpress.org is a sub-domain of that website. And if you look up this domain, you'll see it has a CNAME record. And then the target says WordPress.org. So what that's saying is all the domain name records for me, for this domain, go to WordPress.org and use the same domain records as that domain. So if you're looking for DNS records for make.wordpress.org, the CNAME record says use the same information as if you were looking for WordPress.org. So in this case, the WordPress.org website and the make.wordpress.org website are both owned by the same organization. All the records are the same in the same authoritative name servers. And they actually use a lot of the same values. And so rather than having to type out the same thing again for every sub-domain of the WordPress.org domain, what they've done is I've just set a CNAME record on the sub-domains. So whenever somebody looks up the DNS records for the sub-domain, they're redirected to the records for the main domain. And the main domain owner just has to add all the records in that one place. I hope that makes sense. For the CNAME record, it redirects people to another domain and tells them to use the DNS records for the other domain, the target domain. So you'll see a CNAME record for a domain. It has a value, which is another domain and then time to leave value. So A records the value is an IP address. CNAME records the value is another domain. All right, next, TXT records. TXT is short for text. So these are text notes associated with a domain. Now, when text TXT records were initially created, they didn't really have a purpose. They were more for leaving notes about the domain. You can write whatever you want in a TXT record and your domain will work absolutely fine. You can write like I love orange juice or anything you wanted in a TXT record and it would work fine because TXT records adjust that. They just check text notes about the domain. But in real life scenarios now, TXT records are often used for two purposes. The first one is for domain verification and the second one is for email security. Now we won't go into all the details here, but first of all, domain verification. For example, if you register your domain or say Google Analytics, then Google wants to make sure first of all that you are indeed the owner of that domain before they start sharing analytics information with you. So what Google says is in order for you to verify you actually own this domain, go and copy and paste this piece of text into your DNS record. And if you can add this piece of text into your DNS records, that proves to us you have the login information, you have the access, you are the owner of that domain, and that will prove to us your ownership. So for example, if we look up the WordPress.org domain, if we look at the text records, here we go, text records, you'll see there is a Google site verification and then a key here. So that is what WordPress.org has done. They have registered their domain with some Google account, Google servers, and in the process, they needed to add a value to prove to Google that they do own the domain. And so this is the key Google gave them. So they logged into their account, they added this to the DNS name server to prove to Google they own the domain. So that's one way TXT records are used. Another way TXT records are used is for email security. So we won't go into all the detail here, but for example, if somebody gets an email from WordPress.org, they can access the WordPress.org domain and have a look at these TXT records. This says if your email came from either this IP address or this IP address, then that is from us. So this is telling the world that WordPress.org domain will only send emails from this IP address or this IP address. So if you ever get an email from the WordPress.org domain, but it's originated from a separate IP address, then there's a high possibility it's spam. So that's another way TXT record is used for email security. And you'll see if you have a look at the WordPress.org TXT records, they do have one of those email security text notes here. All right, the last two are a bit more simpler. So the next one, MX record, MX is short for mail exchange, I'm pretty sure, mail exchange record. So MX records direct email to an email server. So before when we had a look at a records, a records tell you the IP address of a web server where the website is stored. MX servers tell you where the mail servers are. So web servers and mail servers are separate. Web servers host website data. So HTML, JavaScript, CSS, et cetera. Mail servers host email data. So you have your inbox, your inbox, you send emails, you save emails, et cetera. And so there are two separate servers. So the A record points people to the web server, the MX record points people to the mail servers. MX records come with a value, which points to a domain name, a time to live value, and also a priority. So depending on your email setup, for example, if you have a lot of email coming in and out, you can have multiple email servers and assign them a priority. And so what people do is, whenever they try and access your web server, they'll, sorry, your mail server, they'll access the one with the highest priority first, but if that one's busy or crowded or down or something, they'll access the second priority and then the third priority, et cetera. You don't need multiple MX records, but some email setups do set them up with multiple records. So in this case, the WordPress.org domain only has one MX record, so there's only just one mail server you need to worry about and it's at mail.wordpress.org. All right. And finally, NS records. NS is short for name server. Basically, these records tell somebody who your authoritative name servers are. So we domain owners get to choose who we make our authoritative name server. And these NS records tell the world who those authoritative name servers are. And generally, it's good practice to have at least three or more NS records added to your domain because if your authoritative name server goes down, nobody can access any of your domain name records. So if they want to send you email, if they want to access your website, if that authoritative name server goes down, they can't do any of that. So it's good practice to have at least two or three authoritative names of a set and have multiple NS records stored. So WordPress.org, let's have a look. If you click NS, you'll see there are three NS records. First one appears as NS3.wordpress.org, NS1.wordpress.org, NS4, and NS2. So these are just four different name servers for the WordPress.org domain. And you can access any of those and they should always have the same information for us. All right, so let me pause again and see if people have any questions. What are DNS records? DNS records are text files that provide information about a domain. And for example, the IP address of a domain or a web server is one piece of information that could be stored as a DNS record. All right, do we have any questions so far? So Bejoy asks, are all these records a CNAME TXC MX present on the authoritative name server? Correct, yes, they are. Let me just go back through my slides. All your DNS records are also stored on your authoritative name server, yes. Actually, that's the only place they're stored. Your DNS, different people's DNS results might cache them from time to time, but if you look at all the right servers here, this is the only place your DNS records are stored. Yep, all right. So somebody asked, can NS server IP addresses differ from A records? So can NAMES server IP addresses differ from A records? Now this was sent to me in the direct message. The answer is yes. In fact, they are probably most often different. So NAMES servers, you would usually set like this. So NS records, you would usually set the domain of your name server. So if you ask your web host, they will tell you what your name servers are. So they will say, for your NS records, add this list of records. So you just have to do what they say. So NS records, you would usually add domains like this as the value, whereas A records are IP addresses. So yes, these will usually differ. And we'll jump into a bit more detail there. So the next question was, where can I edit my domains DNS records? And this sort of connects to the joys question. Where can I edit my domains DNS records? The quick answer is, if you've registered your domain through your web host, then your web host dashboard will have an area to update domain records. So it's important to clarify where you registered your domain is important. So you have your web host, your web host provides you with a web server where you can store your website data. Some web hosts also offer domain services. So you can purchase your domain through your web host, but not all the time. Some web hosts don't offer that. And so what you have to do is you have to purchase your domain from this company and purchase your hosting from that company. So the quick answer is, if you purchase your domain and your web hosting from the same hosting company, then you can update your domain records inside the same dashboard. And sometimes that's not the case. And sometimes you don't want to do it that way. Sometimes domain hosts add extra fees onto domain registration. So sometimes it's cheaper if you go and register your domain from somebody else and your web host from somebody else and connect them later. So it's easiest if they come from the same place, but sometimes it's cheaper if they come from different places. So if that's the case, if you're domain and hosting it from different places, then where do you edit your DNS records? So there are a few steps to this. First of all, you need to choose who your authoritative name servers will be. Are you going to make your web hosts your authoritative name server? Or are you going to make your domain registrar, your authoritative name server? Or are you going to use a third party as your authoritative name server? So where do you want to store your DNS records? So you first need to choose that. And then step two, once you've chosen who your authoritative name servers are, set NS records at your domain registrar to indicate to the world who your authoritative name servers are. So if you're going to use your web host as your authoritative name server, then you need to set NS records at your domain registrar that point to your web host and tell the world my authoritative name servers are over there. And then once you've set that or your other records, you can set within your authoritative name server. So let me turn that into a bit of a picture so it's a bit easier to understand. So the first example, if you registered your domain through your web host, then your domain and your website data are all in the same company. And so you can edit your domain records there too. And if you contact support at your web host, they should be able to edit your domain records for you also. But it gets tricky if your domain was registered as a separate company to your web host. In this case, you want to choose, do you want to make your domain registrar your authoritative name servers or do you want to make your web host, your authoritative name server? So if you want to make your web host, your authoritative name server, what you do is you just set NS records at the domain registrar and then everything else you set at your web host. So you set NS records up at your registrar and then everything else, A records, MX records, TXT records, all of that you set inside your web host. But in example three, if you want to use your domain registrar servers as your authoritative name server, then what you would do is you would set all your domain records here inside your domain registrar, but you would also set a A record that points to your web host because you want to tell the world where your website data is stored. So that's the difference between example two and example three. Example two is you just set NS records at your domain registrar and everything else at your web host. Or in example three, you set everything at your domain registrar and just use A records to point people to your web host. How many people in the call are familiar with, for example, Cloud Flare? Cloud Flare is a third party service that add different security to your domain like they can protect you from brute force attack, et cetera. So if Cloud Flare comes into the picture, they are actually a third person in the triangle. So for example, you would, at your domain registrar, you would set NS records that point to Cloud Flare and then you would set all your other records inside Cloud Flare and use an A record to then post to point to your web host. So hopefully that gives you an idea of what NS records are used for and what A records are used for. All right, so I got a question here. What is the DNS SIG and can you compare any difference with DNS? DNS SIG, is that a domain record type? Let me just go back through my slides. DNS SIG, is that, am I looking at, I was thinking of DNS key, DNS SIG. Security extensions are a suit of extension specifically by the internet or securing data exchange in the internet system in the internet protocol network. I am not knowledgeable about that. Can you compare any difference with DNS? I would have to look into that actually, that's a new concept for me. But it looks like it's an additional protocol to DNS. So DNS communicate with each other fine and DNS SIG is an added security on top of that would be my guess, having just a quick look through this document. But let me look into that. That is a new idea and I am interested in finding out more about that. So we just have a few more slides to get through. If you have any questions, keep dropping them in there. This one is easy. So what DNS records do I need for my SIG? Every SIG needs DNS records. You need to set nameserver records so the world knows who your authoritative nameservers are. Sometimes your, for example, if you purchase your domain from your web host they will set these for you automatically but somebody has set them. Either you set them or somebody else set them for you. Domains will always have a net records. If your domain has a website attached to it then you will always have an A record as well. Again, sometimes web hosts do this for you automatically so you might not have to set it yourself but somebody has to set an A record for your website to connect to your domain. If you have any email services with your domain then you will use MX records. So whether that's an email inbox or even just email forwarding. If you have any type of mail service connected to your domain you will always have MX records. But the question is what specific record should I set? And the answer is, I don't know and you have to connect to your service providers and they will give you the answer. So for example, what NS records should you use? Once you've chosen who's going to be your authoritative name servers, contact them. Ask them what NS records should I use and they will be able to tell you the NS records you need. A records, contact your web host and they will be able to tell you. MX records, contact your email provider and they will be able to tell you. Often MX records, you'll have to add TXT records and DNS D-set key records and other sort of security related records with your MX records. But again, your email provider will be able to tell you exactly what records you need to set. So depending on your record you might have to go to a few different people to ask them what domain records you need to set. Okay, so what the DNS records I need from my site. And the final topic we'll have a look at today is domain record propagation. So whenever you set domain name records there's a thing that's called propagation that happens. So what is that? So we had a look before at the time to live value, the TTL value. And we talked about how domain records are cached in the servers. So a server doesn't have to keep going back and forth, back and forth asking the same information over and over again, it's a time to live value. So for example, you can keep the same record for four hours not have to bug all the other DNS records. You can just use that stored information for the next four hours. And so it has that stored insight. Now the problem is while it's stored back for four hours and for example, if you go and change your DNS records the DNS resolver won't come asking for the information because the old record had a four hour time to live value. And so the DNS resolver thinks it's safe for four hours. But if you've made any changes then you might have to wait four hours before the DNS resolver comes back and asks you for that record and it gets the newest information. So caching helps speed up the internet but whenever you make a change it means there's a time lag before that change is reflected on everyone's computer. So bring up this diagram again, where does caching happen? Caching happens at least in five places. So first of all, when you type a web address into your browser, your browser can actually cache IP addresses so it doesn't even have to go to the DNS resolver. After your browser, your operating system also caches DNS information. So there are two caching mechanisms that happen before you compute that even reaches out to the DNS resolver. And again, anything that happens beyond this arrow everything over here happens on the internet. So it has two caching mechanisms so if it doesn't have to connect to the internet all the better, all the information is just accumulated inside your computer. The DNS resolver also caches information and actually the TLD name server and the authoritative name server also cache information. So for example, if a DNS record has a four hour time to leave value and you make a change here but all these places have cached it then already that's four times four four plus four plus four plus four plus four is 20 hours it takes before all these caches are cleared and your new information finally reaches the computer. So hopefully this gives you an idea about why caching can make changes happen slowly. And so the process of new information getting to all these servers, all these devices that process is called propagation. So when you update DNS the propagation can take hours, sometimes days before the new information reaches all the devices around the world. Is there anything we can do about that? Not really DNS propagation takes time and when I was doing customer support we would usually say you have to wait up to three days. Sometimes propagation doesn't happen, it's very short like just an hour or two and things update but in the worst case scenario it can take up to three days before the newest information is all around the world. So if you have like a major brand launch or product launch or you've created a new website and it was a hidden website for a while but you're going to update the DNS records and make your website public, just keep in mind it might take three days before everybody can actually access your website and see that newest information. So it's good to sort of soft launch things a bit earlier and then have a public announcement a few days in. And there are free websites out there that help you check DNS propagation. So for example, we have this one here called DNS Checker and what you can do is you can type a domain name. You can select which domain name records you want to look up. We're just going to go with A and then do a search. And then what this is doing is it's connecting to different DNS servers all around the world to see if their information matches. So all these green ticks mean these different servers in the world have the same information regarding the A records of WordPress. So if everyone has the same information it probably means propagation has completed. If different servers have different informations then this would actually show like red crosses or orange exclamation marks it'll have different symbols here. I mean this case for example Miami United States has a red cross, this server was down and so the DNS checker website couldn't access it. So sometimes DNS servers go down like that and that's why different DNS servers all across the world have copies of the information so that even if one goes down one of the other ones can still provide that. All right, so that is domain record propagation. And that is all I had. Thank you for listening. Were there any final questions people wanted to ask that I could answer? The Joy asked, is it possible for us to see the actual DNS records for your website? So you can look up the DNS records here, let's see. So for example my Japanese blog is actually more current been logged. So you can type any domain here and this will show you the domain records for that website. So for example my Japanese blog, been the blog has an A record, so that's an IP version four record but my domain actually has a A, A, A, A record as well which is an IP version six record. So people can access my website with an IP version four web browser or an IP version six web browser. Let me see, do I have email? I do have email set up, MX is there. You can see my name servers, et cetera. Great question, okay Gulsion has a question. Can we secure or hide our DNS information from hackers? So yes and no, so yes, sorry, no is quicker. So no because your website is public. Your website is public, so the IP address of your web server has to be public so people can access your websites. Like if that IP address wasn't public people wouldn't know what web server to connect in the world to see your website. So there are some DNS records that have to be public if your website is public. That being said, some DNS records don't need to be public. And so if you use a service like Cloudflare they can sort of monitor who's accessing your DNS records. So if you make Cloudflare your authoritative name servers, they have a record like a blacklist of different bad people on the internet. And so what they can see is if any of those blacklisted people try and access your domain records on their authoritative name servers they will block access from that blacklisted people. So your DNS records might still be public but they're not shown to these specific people. So can you hide your DNS records? The quick answer is no, they have to be public for people to access your websites. But there are services out there that can give you some protection from bad people like that. Yeah, great. A few people have said thank you, very informative. I'm glad it was informative. Clearly loves concepts that is excellent. That's pretty much all I had prepared. Maya, did you want to close off for us? Thank you very much, Ben, for giving us your time. And I hope that people love your session and find some valuable feedback from students.