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By Bhupinder Rajput

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Route 53
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Route 53

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We can use Route-53 to register new domains, transfer existing domains,

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route traffic for our domains to our AWS and external resources and monitor

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the health of our resources.

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• DNS TCP port number is 53.This is the reason why amazon used the name

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Route 53.

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1.DNS Management

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Route-53

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•

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2.Traffic Management

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• 3.Availability Monitoring
Functions • 4.Domain Registration
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Route 53 (Contd..)

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Route-53 performs three main functions :

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1.Register a domain.

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2.As a DNS, it routes internet traffic to the resources for our domain.

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• 3.Check the health of our resources.

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Route-53 sends automated requests over the internet to a resource (can be a

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webserver) to verify that the server is, reachable functional or available.

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o Also we can choose to receive notifications when a resource becomes

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unavailable and choose to route internet traffic away from unhealthy resources

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• We can use Route-53 for any combination of these functions :

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o EX : We can use Route-53 both to register our domain name and to route
internet traffic for the domain.
o Or we can use Route-53 to route internet traffic for a domain that we
registered with another domain register. 3
Route 53 (Contd..)

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• When we register a domain with Route-53,the service automatically makes

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itself the DNS service for the domain by doing the following :

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1. It creates a hosted zone that has the same name as our domain.

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2.It assigns a set of four name servers to the hosted zone, unique to the account.

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o When someone uses a browser to access our website, these name servers

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inform the browser where to find our resources, such as a web server or an

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Amazon S3 bucket.

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o It gets the name servers from the hosted zone and adds them to the domain.

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Route 53 (Contd..)

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AWS Supports

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• 1.Generic Top level. Domains.com,.org,.net etc.

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• 2.Geographic Top Level Domains......in,.us,.me etc.

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Registering a domain with Route-53

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• We can register a domain with route-53 if the TLD is included on the supported TLD list.

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• If the TLD is not included, we can't register the domain with route-53.

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Using Route-53 as our Service

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• We can use Route-53 as the DNS service for any domain, even if the TLD for the domain

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is not included on the supported TLD list.
• Note : Each amazon Route-53 account is limited to a maximum of 500 hosted zones and
10,000 resource record sets per hosted zone. We can increase this limit by requesting to
AWS.
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Route 53 (Contd..)

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Steps to configure Route-53

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• 1.We need to register a domain, this can be route-

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53,or another DNS registrar, but then we connect

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our domain name in that registrar to route-53.

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• 2.Create hosted zone on route-53 (if we

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purchased domain from registrar other than route-

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53), this is done automatically if we registered our

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domain using route-53.
• Inside the hosted zone, we need to create record
sets.
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Route 53 (Contd..)

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Delegate to Route-53

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• This step connects everything and make it works.

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• Connect the domain name to the route-53 hosted zone. This is called delegation.

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• Update our domain registrar with the correct name servers for our route-53 hosted zone.

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• No other customer hosted zone will share this delegation set with us.

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• Doing this means route-53 DNS service will be serving DNS traffic for the domain of the hosted zone.

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• If we registered our domain with a diff registrar, we need to configure the route-53 NS's list in our registrar

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DNS database for our domain.

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When we are using another domain provider and we did all the changes

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• When we migrate from one DNS provider to another, For an existing domain this change can take upto 48

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hours to be effective.

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• This is because name server DNS records are typically cached across the DNS system globally on the

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internet for upto 48 hours (TTL) periods.

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Transferring a Domain to Route-53

• We can transfer a domain to route-53 if the TLD is included on the Amazon supported TLD list.
• If the TLD is not included, we cant transfer the domain to Route-53.
• For most TLD, we need to get authorization code from the current registrar to transfer a domain.
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Route 53 (Contd..)

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Route-53 Hosted Zone

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• A route 53 hosted zone is a collection of records for a specified domain.

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• We create a hosted zone for a domain and then we create records to tell the domain name system how we

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want traffic to be routed for that domain.

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• Basically a hosted zone is a container that holds information about how we want to route traffic for domain

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and its sub domains.

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• We can create public (internet) hosted zone or private (internal) hosted zone.

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• For each public hosted zone that we create amazon route 53 automatically creates name server (ns) record

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and a start of authority (SOA) record. Don't change these records.

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• Route 53 automatically creates a name server (ns) record with the same name as our hosted zone.

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• It list the four name servers that are authoritative name servers for our hosted zone.

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• Do not add, change or delete name servers in this record.

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• When we create a hosted zone, amazon route-53 automatically creates a name server (ns) records and a

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start of authority record (SOA) for the zone.

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• The ns record identifies the four name servers that we give to our registrar or our DNS service so that DNS

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queries are routed to route53 name servers.
• By default route-53 assigns a unique set of four name servers (known collectively as a delegation set).
• Ex : ns-1337 awsdns-39.com
• ns-895 awsdns-47.net
• ns-428 awsdns-53.org
• ns-1597 awsdns-07.co.uk
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Route 53 (Contd..)

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Route 53 as our Authoritative DNS

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•Once we update the route 53 NS settings with our domain registrar to include the route 53

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name server, route 53 will be responsible to respond to DNS queries for the hosted Zone.

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•This is true whether we do have a functioning website or not.

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•Route53 will respond with information about the hosted zone whenever someone types the

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associated domain name in a web browser.

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•We can create more than one hosted zone with the same name and add diff records to each hosted

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zone.

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•Route 53 assigns four name servers to every hosted zone.

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•The name servers are diff for each of them.

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•When we update our registrars name server records, be careful to use the route 53 name servers

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for the correct hosted zone the one that contains the records that we want route 53 to use when

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responding to queries for our domain.

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•Route 53 never returns values for records in other hosted zone that have the same name

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Route 53 Hosted zone default entries

•Inside the hosted zone by default we have two entries :

•NS Entry : Contains the unique sets of name servers for this hosted zone.
•SOA entry : Contains information about the hosted zone . 9
Route 53 (Contd..)

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DNS Record Types

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•If we are currently using another DNS service and we want to migrate to Amazon Route 53 :

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•Start by creating Hosted Zone.

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•Route 53 automatically assigns the delegation sets, the four name servers to our hosted zone.

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•To ensure that the DNS routes queries for our domain to the route 53 name servers.

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•Update our registrar's or our DNS servers NS records for the domain to replace the current Name

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servers with the names of the four Route 53 name servers for our hosted zone.

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•The method that we use to update the NS records depends on which registrar or DNS service we

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are using.

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•Some registrar only allow us to specify name servers using IP addresses they dont allow us to

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specify fully qualified domain names.

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•If our registrar requires using Ip addresses, we can get the IP addresses for our name servers

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using the dig utility (for mac and Linux) and nslookup( for windows).

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Transferring a domain between accounts within AWS

•Transferring a domain to a diff AWS account :

•If we registered a domain with one AWS account and we want to transfer the domain to another
AWS account, we can do so by contacting the AWS support center and Requesting the transfer.
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Route 53 (Contd..)

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Migrating a hosted zone to a diff AWS account

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•If we are using Route53 as the DNS service for the domain, route53 does not transfer the hosted

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zone when we transfer a domain to a diff AWS account.

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•If domain registration is associated with one account and the corresponding hosted zone is

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associated with another account, neither domain registration nor DNS functionality is affected.

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•The only effect is that we will need to sign into the route 53 console using one account to see the

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domain and signin using the other account to see the hosted zone.

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Supported DNS Record Types by Route 53

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•1.A record : Address Record maps domain names to IP Address (32 bit IPv4 Address),

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www.techguftugu.com in A 5.5.5.5

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•2.AAAA Record : IPv6 address record maps domain name to an IPv6 address (128 bit IPv6

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address so the name AAAA [32bits*4]).

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•3.CNAME Record : Canonical name record maps an alias to a hostname. Web in CNAME

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techguftugu.com.
•4.NS record : Name server Record used for delegating zone to a nameserver. techguftugu.com in
NS ns1.techguftugu.com.
•5.SOA Record : Start of Authority Record.
•6.MX record : Mail exchange defines where to deliver mail
for user@domain name.techguftugu.com in MX 10 mail.techguftugu.com. 11
Supported DNS Record Types by Route 53

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NS record

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• It defines which name server is an authoritative to a particular zone or domain name and point us to other DNS servers.

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• A/AAAA are called host records, like business cards.

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• CNAME is an alternative records, or an alias for another record.

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• Helpful in redirection or if we want to hide details about our actual servers from the user.

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SOA Record

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• Every single zone has one and only SOA resource record at the beginning of the zone.

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• It is not an actual record, it includes the following info :

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• Who the owner is (email for the domain).

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• The authoritative server.

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• The serial number which is incremental with changes to the zone data.

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• The refreshing time/cycle info and the time to live (TTL).

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CNAME Record

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• A CNAME value element is the same format as a domain name.

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• The DNS protocol does not allow us to create a CNAME record for the top node of a DNS namespace, also known as the zone apex (or
root domain).
• For EX : if we register the DNS name techguftugu.com, the zone apex is techguftugu.com and we cannot create a CNAME
for techguftugu.com.
• However we can create CNAME records for WWW.techguftugu.com,support.techguftugu.com and so on.
• In addition, if we create a CNAME record for a subdomain we cannot create any other record for that Subdomain.
• EX: If we create a CNAME for www.techguftugu.com we cannot create any other records for which the value of the name
field is www.techguftugu.com . 12
Supported DNS Record Types by Route 53

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CNAME Record

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• A CNAME value element is the same format as a domain name.

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• The DNS protocol does not allow us to create a CNAME record for the

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top node of a DNS namespace, also known as the zone apex (or root

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domain).

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• For EX : if we register the DNS name techguftugu.com, the zone apex is

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techguftugu.com and we cannot create a CNAME for techguftugu.com.

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• However we can create CNAME records

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for WWW.techguftugu.com,support.techguftugu.com and so on.

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• In addition, if we create a CNAME record for a subdomain we cannot

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create any other record for that Subdomain.
• EX: If we create a CNAME for www.techguftugu.com we cannot create
any other records for which the value of the name
field is www.techguftugu.com .
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Routing Policy

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Routing Policies

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• When we create a record, we choose a routing policy, which determines

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how amazon route 53 respond to Queries.

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• Simple, Failover, Geo Location, Latency, Geo Proximity, Weighted and

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Multi-Level Routing Policies.

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Failover Routing Policy

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• Failover routing lets us route trafiic to a resource when the resource is

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healthy if the main resource is not healthy, then route traffic to diff

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resource.
• The primary and secondary records can route traffic to anything from an
amazon S3 buccket that is configured as a website to a complex tree of
records.
• Failover routing policy is applicable for public hosted zone only. 14
Geolocation Routing

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It lets us choose the resources that serves our traffic based on the geographic

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location of our users i.e. the location that DNS queries originate from.

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• Ex : We may have presence in Europe and Asia and we want users in the Asia to

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be served in the Asia and those in Europe to be served by servers in Europe.

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• Benefits :

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o We can localize our content and present some or all of our website in the language

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of our users.

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o We can also use geolocation routing to restrict distribution of content to only the

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locations in which we have distribution rights.

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o We can specify geographic locations by continent, by country or by state in the US.

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o If we create separate records for overlapping geographic regions for ex : one record
for North America and one for Canada-priority goes to the smallest geographic
region (Canada).
o Geolocation works by mapping IP address to location. However some IP address 15
are not mapped to geographic location.
Latency Based Routing

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• If our application is hosted in multiple amazon ec2 regions, we can improve performance for our

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users by serving their request from the amazon ec2 region that provides the lowest latency.

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• To use this routing we need to create latency records for our resources in multiple ec2 regions.

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• When amazon route 53 receives a DNS query for our domain or subdomain

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o It determines which amazon ec2 region we have created latency record for.

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o Determine which regions gives lowest latency to users.

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o Then select a latency record for that region

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• Ex : Suppose we have ELB in US-East and in Asia pacific (Mumbai) region.

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We created a latency record for each load balancer.

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Here's what happened when a user in London enters the name of our domain in browser.

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•

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DNS routes the request to a route 53 name server.

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•

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Route 53 refers to its data on latency between London and the Mumbai region and between
London and N.Virginia.
• If latency is lower between London and N.verginia, route 53 respond to the query with the IP address
for the N.verginia LB.
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Weighted Routing Policy

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• It lets us associate multiple resources with a single domain name or subdomain name

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and choose how much traffic is routed to each resource.

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• This can be useful for a variety of purposes, including load balancer and testing new

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versions of software.

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Weights can assign any number from 1 to 255.

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• Weighted routing policy can be applied when there are multiple resource that

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performs the same function. Ex : Webserver serving the same website.

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•

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To configure weighted routing, we create records that have the same name and type

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for each of our resources.

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•

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Amazon route 53 sends traffic to a resource based on weight that we assign to the

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record as a proportion of the total weight for all records in the group.

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• Ex : Suppose for www.tg.com has three resource record sets with weights of 1(20%)
,1(20%) and 3(60%). Sum =5.
• On average, route 53 select each of the first two resources record set one-fifth of the
time and returns the third resource record set three-fifth of the time. 17
Geo Proximity Routing Policy

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• Use when we want to route traffic based on the location of our

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resources and optionally, shift traffic from resources in one location to

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resources in another.

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• We can also optionally choose to route more traffic or less to a given

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resource by specifying a value, known as a ‘bias’. A bias expand or

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shrinks the size of the geographic region from which traffic is routed

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to a resource.

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Multivalued Answer Routing Policy

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• Use this, when we want route 53 to respond to DNS queries with upto eight healthy record

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selected at random.

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This lets us configure amazon route 53 to return multiple values, such as IP addresses for

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our webservers in response to DNS queries. We can specify multiple values for almost

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any record, but multivalue answer routing also lets us check, the health of each resource,

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so route 53 returns only values for healthy resources. Its not a substitute for our load

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balancer but the ability to return multiple health checkable IP addresses is a way to use

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DNS to improve availability and load balancing.

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Name Type​ Value TTl Set I.D H,C

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(HealthCheck)​

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www.tg.com​ A​ 192.0.2.2​ 60​ web1​ A​

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www.tg.com​ A​ 195.50.100. 60​ web2​ B​
1​
www.tg.com​ A​ 200.1.1.1​ 60​ web3​ C​
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www.tg.com​ A​ 192.0.3.3​ 60​ web4​ D​
Th
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Thanks!

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Any questions?

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You can find me at:

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@TechnicalGuftgu

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technicalguftgu99@gmail.com

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