What happens when Route 53 receives a DNS query from a DNS resolver for a subdomain?

Here's what happens when Route 53 receives a DNS query from a DNS resolver for the subdomain apex.example.com or one of its subdomains: 1) Route 53 *looks in the hosted zone for the domain (example.com) and finds the NS record for the subdomain* (apex.example.com). 2) Route 53 *gets the name servers from the apex.example.com NS record in the hosted zone for the domain*, example.com, and returns those name servers to the DNS resolver. 3) The *resolver resubmits the query for apex.example.com to the name servers for the apex.example.com hosted zone*. 4) Route 53 *responds to the query using a record in the apex.example.com hosted zone.*

What needs to happen to route traffic to a subdomain of a subdomain (e.g. backend.apex.example.com)?

The options to route traffic to a subdomain of a subdomain, such as backend.apex.example.com, are the same as for routing traffic to a subdomain, such as apex.example.com. 1) *Create records in the hosted zone for the domain* 2) *Create a hosted zone for the lower-level subdomain, and then you create records in that new hosted zone* -To ensure that traffic is correctly routed to your resources, *create the NS record for a lower-level subdomain in the hosted zone for the subdomain that is one level closer to the domain name*.

What is the *simple* routing policy?

Simple routing *lets you configure standard DNS records*, with *no special Route 53 routing such as weighted or latency*. With simple routing, you *typically route traffic to a single resource*, for example, to a web server for your website. If you choose the simple routing policy in the Route 53 console, *you can't create multiple records that have the same name and type*, *but you can specify multiple values in the same record*, such as multiple IP addresses

What is the *failover* routing policy?

Failover routing *lets you route traffic to a resource when the resource is healthy or to a different resource when the first resource is unhealthy*. The primary and secondary records can route traffic to anything from an Amazon S3 bucket that is configured as a website to a complex tree of records.

What would need to be setup in order to failover to an alternate ELB if the main production website is down?

*Create 2 Health checks*: 1) *Primary site ELB (using ELB domain name) and no alarms*- This checks if there is an issue with all instances behind an ELB. 2) *Main production web site URL* (with alarms configured for notification sent to an email) - Checks if the domain is down. This would suggest that the primary and secondary sites are down. *Setup 2 Alias record*: 1) *Primary Failover Record type* - One Alias record with the *target of the primary ELB/EC2 resource*. *Evaluate Target health = Yes*, *Associate with Health Check=Yes* and health check should be the *health check for the ELB and not for the primary web site*. 2) *Secondary Failover record type* - Set the* alias target = failover ELB* (e.g. Sydney). *Secondary as the failover type*. *Evaluate Target Health and Associate with Health Check are set to No*.

What is the *geolocation* routing policy?

Geolocation routing *lets you choose the resources that serve your traffic based on the geographic location of your users*, meaning the location that DNS queries originate from. Geo DNS *provides three levels of geographic granularity*: *continent*, *country*, and *state*, and Geo DNS also *provides a global record which is served in cases where an end user's location doesn't match any of the specific Geo DNS records you have created*.

What is the *geoproximity* routing policy?

Geoproximity routing lets Amazon Route 53 *route traffic to your resources based on the geographic location of your users and your resources*. You *can also optionally choose to route more traffic or less to a given resource by specifying a value, known as a bias*, that expands or shrinks the size of the geographic region from which traffic is routed to a resource. Note that *can only be done through Route 53 traffic flow*.

What is the *latency-based* (LBR) routing policy?

If your application is hosted in multiple AWS Regions, you *can improve performance for your users by serving their requests from the AWS Region that provides the lowest latency*. To use latency-based routing, *you create latency records for your resources in multiple AWS Regions*. When Route 53 receives a DNS query for your domain or subdomain (example.com or apex.example.com), it *determines which AWS Regions you've created latency records for, determines which region gives the user the lowest latency, and then selects a latency record for that region*. Route 53 responds with the value from the selected record, such as the IP address for a web server.

What are the steps for setting up a latency based policy?

Create a latency resource record set for the resource (EC2/ELB) in each region that hosts a site The region value needs to be the same as the region of the resource (EC2/ELB).

What is the *multivalue answer* routing policy?

Multivalue answer routing *lets you configure Amazon Route 53 to return multiple values, such as IP addresses for your web servers, in response to DNS queries*. You *can specify multiple values for almost any record*, but *multivalue answer routing also lets you check the health of each resource*, so Route 53 returns *only values for healthy resources*. It's *not a substitute for a load balancer*, but the ability to return multiple health-checkable IP addresses is a way to use DNS to improve availability and load balancing.

What is the *weighted* routing policy?

Weighted routing *lets you associate multiple resources with a single domain name or subdomain name* and *choose how much traffic is routed to each resource*. This can be useful for a variety of purposes, including *load balancing* and *testing new versions of software. (aka A/B Testing)*. Note that the ELB's can be in the same region.

What are the steps for setting up a weighted routing policy?

Need to create 2 or more Alias records with an assigned weight to point to the appropriate load balancer/IP.

Does Amazon Route 53 support *Weighted Round Robin (WRR)*?

Yes. Weighted Round Robin allows you to *assign weights to resource record sets in order to specify the frequency with which different responses are served*. You may want to use this capability to do A/B testing, sending a small portion of traffic to a server on which you've made a software change. For instance, suppose you have two record sets associated with one DNS name—one with weight 3 and one with weight 1. In this case, 75% of the time Route 53 will return the record set with weight 3 and 25% of the time Route 53 will return the record set with weight 1. Weights can be any number between 0 and 255.

Can I have a Geo DNS record for a continent and different Geo DNS records for countries within that continent? Or a Geo DNS record for a country and Geo DNS records for states within that country?

Yes, you can have Geo DNS records for overlapping geographic regions (e.g., a continent and countries within that continent, or a country and states within that country). For each end user's location, Route 53 will return the most specific Geo DNS record that includes that location. In other words, for a given end user's location, Route 53 will first return a state record; if no state record is found, Route 53 will return a country record; if no country record is found, Route 53 will return a continent record; and finally, if no continent record is found, Route 53 will return the global record.

When using Geo DNS, do I need a "global" record? When would Route 53 return this record?

Yes, we strongly recommend that you configure a global record, to ensure that Route 53 can provide a response to DNS queries from all possible locations—even if you have created specific records for each continent, country, or state where you expect your end users will be located. Route 53 will return the value contained in your global record in the following cases: The DNS query comes from an IP address not recognized by Route 53's Geo IP database. The DNS query comes from a location not included in any of the specific Geo DNS records you have created.

What is the difference between Latency Based Routing and Geo DNS?

Geo DNS bases routing decisions on the geographic location of the requests. In some cases, geography is a good proxy for latency; but there are certainly situations where it is not. LatencyBased Routing utilizes latency measurements between viewer networks and AWS datacenters. These measurements are used to determine which endpoint to direct users toward. If your goal is to minimize end-user latency, we recommend using Latency Based Routing. If you have compliance, localization requirements, or other use cases that require stable routing from a specific geography to a specific endpoint, we recommend using Geo DNS.

Does Amazon Route 53 support multiple values in response to DNS queries?

Route 53 now supports multivalue answers in response to DNS queries. While not a substitute for a load balancer, the ability to return multiple health-checkable IP addresses in response to DNS queries is a way to use DNS to improve availability and load balancing. If you want to route traffic randomly to multiple resources, such as web servers, you can create one multivalue answer record for each resource and, optionally, associate an Amazon Route 53 health check with each record. Amazon Route 53 supports up to eight healthy records in response to each DNS query.

How can you route traffic to an Amazon CloudFront Web Distribution by Using Your Domain Name?

If you want to use your own domain name, use Amazon Route 53 to *create an alias record of Type A for IPv4 or Type AAAA for IPv6 that points to your CloudFront distribution*. NOTE: You can *route traffic to a CloudFront distribution only for public hosted zones*.

How do you route traffic to an Amazon EC2 instance?

*Create an A record that is not an Alias that points to the public or Elastic IP*

How do you route traffic to an Amazon Elastic Beanstalk environment?

*If the domain name does NOT include the region You must create a CNAME record*. You can't create a CNAME record for the root domain name. For any *environments that were created before early 2016 do not include the region name*. *If the domain name includes the region You can create an alias record of Type A.*

How do you route traffic to an ELB Load Balancer?

To route domain traffic to an ELB load balancer, use Amazon Route 53 to *create an alias record that points to your load balancer with the following attributes*: - Name - *The name that you specify when you create a load balancer is the name that you'll choose when you create an alias record* - Type - Choose *A - IPv4 address*. - *Alias - Choose Yes*. - Alias Target - If you created the hosted zone and the ELB load balancer using the same AWS account - *Find the applicable category in the list* (ELB Application Load Balancers, ELB Classic Load Balancers, or ELB Network Load Balancers), and then *choose the name that you assigned to the load balancer when you created it.*. *If you created the hosted zone and the ELB load balancer using different accounts - Enter the value that you got in step 1 of this procedure.* - *Routing Policy - Accept the default value of Simple.* - Evaluate Target Health - If *you want Route 53 to route traffic based on the health of your resources, choose Yes.*

How can you open connections to an Amazon RDS Database instance using your domain name?

If you want to use a domain name that's easier to remember, you can use your own domain name instead. To do this, you can use Amazon Route 53 to *create a CNAME record that associates your domain name with the domain name of your DB instance.* This would be applicable in code that establishes connections to a RDS database instance.

How can you route traffic to a (static) website that is hosted in an Amazon S3 bucket?

To route domain traffic to an S3 bucket, use Amazon Route 53 to *create an alias record with a Type of A that points to your bucket. * The Name should be the domain name you want to use to route traffic to the S3 bucket. For the Alias Target in the S3 website endpoints choose the bucket that has the same name that you specified for Name. The *Alias Target list includes a bucket only if the bucket meets the following requirements*: - The *name of the bucket is the same as the name of the record that you're creating*. - The bucket is *configured as a website endpoint*. - The bucket was *created by the current AWS account.* If you created the bucket using a different AWS account, type the name of the region that you created your S3 bucket in. For the correct format for the region name, see the Website Endpoint column in the Amazon Simple Storage Service Website Endpoints table in the AWS Regions and Endpoints chapter of the Amazon Web Services General Reference.

How can you route traffic to Amazon WorkMail?

Summary: - *Create Route 53 TXT, MX and 4 CNAME records* Details: To route traffic to Amazon WorkMail, *perform the following four procedures.* 1) *configure Amazon Route 53 as your DNS service and add an Amazon WorkMail organization and email domain* 2) *create a Route 53 TXT record for Amazon WorkMail with the following settings* - - Name - Copy the first part of the hostname that precedes the email domain from the WorkMail console (For example, if your Amazon WorkMail email domain is example.com and the value of Hostname is _amazonses.example.com, copy _amazonses.). This is the value to use for the Name of the TXT record. - Value - The Value field should be copied from Value field on the TXT record in the WorkMail console (including quotation marks). 3) *Create a Route 53 MX record for Amazon WorkMail with the following settings* - - Value - In the Amazon WorkMail console, in the section Step 2: Finalize domain setup, go to the row that has a Record type of MX, and copy the value of the Value column. - Type - MX 4) *Create four(4) Route 53 CNAME records for Amazon WorkMail with the following settings* - - Name - In the Amazon WorkMail console, in the section Step 2: Finalize domain setup, go to the first row that has a Record type of CNAME. In the Hostname column, copy the part of the value that precedes your email domain name and paste this into the Name field of the Route 53 CNAME record - Type - CNAME - Value - In the Amazon WorkMail console, in the first row that has a Record type of CNAME, copy the value of the Value column and paste that into the Value field of the Route 53 CNAME record. NOTE: You *can route traffic to an Amazon WorkMail domain only for public hosted zones.*