Amazon Route 53 | DNS Routing Policies Flashcards
Why does the DNS Query Test Tool return a response different than the dig or nslookup commands?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
When resource record sets are changed in Amazon Route 53, the service propagates updates you make to your DNS records to its world-wide network of authoritative DNS servers. If you test the record before propagation is complete, you may see an old value when you use the dig or nslookup utilities. Additionally, DNS resolvers on the internet are outside the control of the Amazon Route 53 service and will cache your resource record sets according to their time to live (TTL), which means a dig/nslookup command might return a cached value. You should also make sure that your domain name registrar is using the name servers in your Amazon Route 53 hosted zone. If not, Amazon Route 53 will not be authoritative for queries to your domain.
Does Amazon Route 53 support Weighted Round Robin (WRR)?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
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.
What is Amazon Route 53’s Latency Based Routing (LBR) feature?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
LBR (Latency Based Routing) is a new feature for Amazon Route 53 that helps you improve your application’s performance for a global audience. You can run applications in multiple AWS regions and Amazon Route 53, using dozens of edge locations worldwide, will route end users to the AWS region that provides the lowest latency.
How do I get started using Amazon Route 53’s Latency Based Routing (LBR) feature?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
You can start using Amazon Route 53’s new LBR feature quickly and easily by using either the AWS Management Console or a simple API. You simply create a record set that includes the IP addresses or ELB names of various AWS endpoints and mark that record set as an LBR-enabled Record Set, much like you mark a record set as a Weighted Record Set. Amazon Route 53 takes care of the rest - determining the best endpoint for each request and routing end users accordingly, much like Amazon CloudFront, Amazon’s global content delivery service, does. You can learn more about how to use Latency Based Routing in the Amazon Route 53 Developer Guide.
What is the price for Amazon Route 53’s Latency Based Routing (LBR) feature?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
Like all AWS services, there are no upfront fees or long term commitments to use Amazon Route 53 and LBR. Customers simply pay for the hosted zones and queries they actually use. Please visit the Amazon Route 53 pricing page for details on pricing for Latency Based Routing queries.
What is Amazon Route 53’s Geo DNS feature?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
Route 53 Geo DNS lets you balance load by directing requests to specific endpoints based on the geographic location from which the request originates. Geo DNS makes it possible to customize localized content, such as presenting detail pages in the right language or restricting distribution of content to only the markets you have licensed. Geo DNS also lets you balance load across endpoints in a predictable, easy-to-manage way, ensuring that each end-user location is consistently routed to the same endpoint. 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. You can also combine Geo DNS with other routing types, such as Latency Based Routing and DNS Failover, to enable a variety of low-latency and fault-tolerant architectures. For information on how to configure various routing types, please see the Amazon Route 53 documentation.
How do I get started using Amazon Route 53’s Geo DNS feature?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
You can start using Amazon Route 53’s Geo DNS feature quickly and easily by using either the AWS Management Console or the Route 53 API. You simply create a record set and specify the applicable values for that type of record set, mark that record set as a Geo DNS-enabled Record Set, and select the geographic region (global, continent, country, or state) that you want the record to apply to. You can learn more about how to use Geo DNS in the Amazon Route 53 Developer Guide.
When using Geo DNS, do I need a “global” record? When would Route 53 return this record?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
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.
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?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
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.
What is the price for Route 53’s Geo DNS feature?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
Like all AWS services, there are no upfront fees or long term commitments to use Amazon Route 53 and Geo DNS. Customers simply pay for the hosted zones and queries they actually use. Please visit the Amazon Route 53 pricing page for details on pricing for Geo DNS queries.
What is the difference between Latency Based Routing and Geo DNS?
DNS Routing Policies
Amazon Route 53 | Networking & Content Delivery
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.
