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00:00:00,540 --> 00:00:02,850
‫So now that we know what is a DNS,

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‫let's have a look at Amazon Route 53.

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‫So this is a highly available, scalable,

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‫and fully managed and authoritative DNS.

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‫What does authoritative means?

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‫That means that the customer you can update the DNS records,

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‫so you have full control over this DNS.

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‫So the idea is that you have your clients

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‫and they want to access your EC2 Instance @example.com

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‫but right now your EC2 Instance only has a public IP.

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‫Therefore what's going to happen

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‫is that we're going to write some DNS records

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‫into Amazon Route 53, into a hosted zone,

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‫and when the client is asking for example.com,

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‫then the Route 53 service will be able to say,

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‫"Hey, you're looking for this IP 54.22.33.44,"

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‫and then the clients will be able to connect directly

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‫into our EC2 Instance.

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‫So Route 53 is also a domain registrar,

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‫so it will be able to register our own domain names there

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‫such as example.com, and we'll be doing this

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‫in the hands-on to allow us to get started

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‫with this service.

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‫So we have the ability to check also the health

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‫of the resources within Route 53,

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‫we'll see this in the section.

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‫And this is the only service in AWS

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‫that will provide 100% availability SLA.

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‫Finally, why is it called Route 53?

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‫Well, 53 is a reference to the traditional DNS port

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‫used by DNS services, hence the name.

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‫So in Route 53 you're going to define a bunch of DNS records

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‫and the records define how you want to route traffic

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‫to a specific domain.

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‫So each record is going to contain a lot of information

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‫such as the domain or the subdomain names

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‫such as example.com.

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‫The record type, and we'll see what types of record

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‫we have available to us, for example it could be A or AAAA.

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‫Then the value, so the value of the record,

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‫for example, 12.34.56.78

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‫The routing policy,

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‫which is how a Route 53 will respond to queries.

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‫The TTL, which is the amount of time

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‫the record is going to be cached at the DNS resolvers,

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‫also called time to live.

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‫And then we have a lot of different supported

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‫DNS report types in Route 53.

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‫So we have, the ones you must know is A, quadruple A,

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‫CNAME, and NS, so we'll have a look at those

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‫in the hands-on.

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‫And the advanced records that you can set,

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‫but we don't need to know from an exam perspective,

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‫are all the ones I just wrote right here.

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‫So let's learn about the important record types

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‫we need to know from an exam perspective.

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‫So the A record is very simple,

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‫it's to map a host name into an IPv4 IP.

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‫So this is when you have, for example, example.com

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‫that will be directed into 1.2.3.4.

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‫Okay, great.

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‫Then we have quadruple A.

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‫So this is the same idea as A,

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‫but this time we're going to match our host name

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‫into an IPv6 address.

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‫Then we have a CNAME, which is used to map a host name

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‫into another host name.

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‫And then the target host name of course may be an A

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‫or a quadruple A record.

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‫You can not create CNAMES in Route 53

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‫for the top nodes of a DNS namespace or the Zone Apex,

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‫and we'll see this in a future lecture as well

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‫to understand how that works.

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‫For example, you can not create a CNAME for example.com,

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‫but you can create a CNAME record for www.example.com.

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‫So we'll see how we can deal with this in a future lecture.

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‫And then finally, NS is for name servers of the hosted zone.

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‫They are the DNS names or IP addresses of the servers

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‫that can respond to the DNS queries for your hosted zone,

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‫and this will control how traffic is routed to a domain.

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‫So let's have a look at what are hosted zones.

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‫So hosted zones are a container of records,

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‫and they will define how to route traffic

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‫to a domain and its subdomain.

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‫So we have two types of hosted zone,

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‫we have the public of zones and the private hosted zones.

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‫So whenever you buy a public domain name,

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‫for example mypublicdomain.com, this is a public domain name

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‫and therefore we can create a public hosted zone

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‫and these public zone can answer the query,

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‫"Hey, what's is the IP, underlying IP of the domain name

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‫application1.mypublicdomainname.com?"

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00:04:04,870 --> 00:04:06,750
‫But we also have private hosted zones.

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‫And these are for domain names that you,

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‫they are not publicly available, they're privates,

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‫and only you within your own virtual private cloud or VPC

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00:04:15,150 --> 00:04:16,410
‫can resolve this URL.

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‫For example, application1.company.internal.

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00:04:19,830 --> 00:04:21,090
‫You may have seen this if you're working

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‫for a private company, they sometimes have URLs

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‫that you can only access from within your corporate network,

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‫that's because this is a private URL, this is a private

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‫and behind the scenes there is a private DNS record.

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00:04:32,360 --> 00:04:35,840
‫So for any hosted zones you're going to create an AWS

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‫you're going to pay 50 cents per month,

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‫so this is not free to use Route 53.

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‫And if you are to register a domain name,

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‫just like I will in the hands-on,

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‫this will cost you a minimum of a $12 per year.

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00:04:47,620 --> 00:04:49,920
‫So just so you know, this section is not free.

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00:04:51,400 --> 00:04:54,490
‫So public versus private hosted zones, just to understand.

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00:04:54,490 --> 00:04:57,050
‫So public hosted zone can be answered,

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00:04:57,050 --> 00:04:59,110
‫can answer queries from public clients.

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00:04:59,110 --> 00:05:00,477
‫So when you web browser, for example, and say,

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00:05:00,477 --> 00:05:04,070
‫"Hey, give me example.com," and then it returns an IP.

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00:05:04,070 --> 00:05:07,110
‫And on the other end we have the private hosted zone.

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00:05:07,110 --> 00:05:09,630
‫So this is from within your VPC they live.

118
00:05:09,630 --> 00:05:12,340
‫And so they allow you to identify private resources

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00:05:12,340 --> 00:05:14,640
‫with private domain names.

120
00:05:14,640 --> 00:05:16,970
‫So for example, we have one EC2 Instance

121
00:05:16,970 --> 00:05:20,110
‫that we want to identify with webapp.example.internal,

122
00:05:20,110 --> 00:05:22,330
‫we have another EC2 Instance that we want to identify

123
00:05:22,330 --> 00:05:25,430
‫with api.example.internal, and then we have a database

124
00:05:25,430 --> 00:05:29,120
‫we want to identify with database.example.internal.

125
00:05:29,120 --> 00:05:32,030
‫In which case we're going to register a private hosted zone,

126
00:05:32,030 --> 00:05:34,170
‫and then in case the first EC2 Instance

127
00:05:34,170 --> 00:05:37,140
‫is requesting for api.example.internal,

128
00:05:37,140 --> 00:05:39,660
‫then the private hosted zone has an answer for it,

129
00:05:39,660 --> 00:05:42,770
‫which is the private IP 10.0.0.10.

130
00:05:42,770 --> 00:05:43,900
‫Then the EC2 Instance will connect

131
00:05:43,900 --> 00:05:45,220
‫to the second EC2 Instance,

132
00:05:45,220 --> 00:05:46,530
‫which may need to connect to database.

133
00:05:46,530 --> 00:05:49,800
‫So it will say, "Hey, what's database.example.internal?"

134
00:05:49,800 --> 00:05:51,087
‫And the private hosted zone will say,

135
00:05:51,087 --> 00:05:52,970
‫"Well, this is this private IP."

136
00:05:52,970 --> 00:05:54,920
‫And then the EC2 Instance can connect directly

137
00:05:54,920 --> 00:05:56,280
‫into the database.

138
00:05:56,280 --> 00:05:58,220
‫So the public hosted zone and the private hosted zone

139
00:05:58,220 --> 00:06:00,780
‫work the exact same way, but just the public hosted zone

140
00:06:00,780 --> 00:06:03,300
‫allows anyone from the internet to query your records,

141
00:06:03,300 --> 00:06:05,080
‫so this is for your public records,

142
00:06:05,080 --> 00:06:07,700
‫whereas a private hosted zone is only queried

143
00:06:07,700 --> 00:06:11,350
‫from within your private resources, for example your VPC.

144
00:06:11,350 --> 00:06:12,610
‫So that's it for the theory,

145
00:06:12,610 --> 00:06:15,010
‫now let's go into the next lecture to register a domain

146
00:06:15,010 --> 00:06:16,430
‫and then create some records.

147
00:06:16,430 --> 00:06:18,330
‫So I will see you in the next lecture.