DNS Flashcards
Do ELBs have an IP address?
No, you resolve them using a DNS name
What is an A record?
The Arecord maps a name to one or more IP addresses when the IP are known and stable.
What is a CNAME?
TheCNAMErecord maps a name to another name. It should only be used when there are no other records on that name.
What is an alias?
TheALIASrecord maps a name to another name, but can coexist with other records on that name.
If you need to map a domain to a bucket what should you use?
An Alias record
Name 5 common DNS types?
1) SOA (start of authority) record- name of server, administrator..
2) NS (Name Server)
3) A record
4) CNAME
5) MX record (mail server)
6) PTR record (IP to Domain name)
What are the 7 routing policies available on Route53?
1) Simple routing
2) weighted routing
3) latency routing
4) fail over routing
5) Geolocation routing
6) Geoproximity routing
7) multivalue answer
How can health checks be used with Route53?
A health check can be used to check the status of a record set. if a record set fails health check it will be removed from Route53 until it passes the health check
Can you set up SNS notifications with Route53
Yes you can get notification if a health check has failed
What is a simple routing policy?
A if you choose a simple routing policy you can only have one record with multiple IP addresses associated. When a request is made Route53 will return all values to the user in a random order.
What is a weighted routing policy?
e.g. Diverting traffic…. 20% USA-1, 80% USA-2
What is latency based routing?
Uses the physical location of the user to determine the latency and speed of transfer and diverts traffic to the lowest latency option.
What is failover based routing?
Use health checks to define active and passive resources and allows rerouting if a given IP address fails a health check
What is geolocation routng?
Makes routing decisions based on the location of the user… nothing to do with latency!!
What is a multi value answer policy?
A routing policy that is the same as simple routing bit includes health checks as well!
