What is DNS?
DNS Stands for Domain Name System and is used to map a human readable domain names to an IP address and vice versa.
www.abc.com → 192.168.10.1
Common DNS Record Types
Short for Start of Authority record and contains administrative information about the domain or zone. A SOA record includes the following details,
- <name>: zone name
- <class>: network class
- <type>: record type
- <mname>: master name
- <rname>: email address for the responsible administrator
- <serial>: incremental serial number that specifies the zone file version
- <refresh>: time specification when a slave must request the current master version
- <retry>: time specification when a slave is supposed to again perform a failed request attempt
- <expire>: time specification from which a slave does not release further information in the absence of feedback from the master
- <minimum>: time specification for how long information may be retained in a cache
Name Server records identify which name server is responsible for your DNS zone.
Amazon Route 53 automatically creates a NS record and a SOA record for each public hosted zone that a user create.
A (Address) record is used to translate a domain name to an IPv4 address. For IPv6 AAAA records are used.
Canonical Name record maps one domain name to another. Imagine having a subdomain ‘info.abc.com’ for the domain ‘abc.com’ and you have a CName record for that. Then whenever a DNS server hits the DNS record for info.abc.com it’ll trigger an DNS lookup for ‘abc.com’.
Alias records operate similar to CName records but maps resource record sets in your hosted zone to AWS resources.
Simple Routing Policy
Use for a single resource that performs a given function for your domain, for example, a web server that serves content for the example.com website.
The simplest routing policy that allows you to have a single record with multiple values. And Route 53 return the values randomly.
Weighted Routing Policy
Use to route traffic to multiple resources in proportions that you specify.
Latency Routing Policy
Use when you have resources in multiple AWS Regions and you want to route traffic to the region that provides the best latency.
Need to create a latency resource record set for each region that you have resources. When Route 53 receives a DNS query the latency resource record for the region that gives the lowest latency is selected.
Failover Routing Policy
Use when you want to configure active-passive failover.
Route 53 monitors the health of the primary site using health checks. And when the primary site goes down (health check fails) Route 53 will failover to the passive site.
Geolocation Routing Policy
Use when you want to route traffic based on the location of your users. (Based on the location from which the DNS query originated)
Geoproximity Routing Policy
Use when you want to route traffic based on the location of your resources and users. And optionally, route more or less traffic to a given resource using a bias. A bias expands or shrinks the size of the geographical region from which traffic is routed to a resource.
In order to use Geoproximity routing, Route 53 traffic flow must be used.
Multivalue answer routing policy
Use when you want Route 53 to respond to DNS queries with up to eight healthy records selected at random.
Similar to simple routing but you can use health checks for failovers.