Route53 class
- 1. What is DNS? • If you've used the internet, you've used DNS. DNS is used to convert human friendly domain names (such as http://amazon.com) into an internet Protocol(IP)address(72.21.215.90). • IP addresses are used by computers to identify each other on the network. IP addresses commonly come in 2 different forms, IPv4 and IPv6
- 2. IPv4 vs IPv6 • The IPv4 space is a 32 bit field and has over 4 billion different addresses (4,294,967,296 to be precise). • IPv6 was created to solve this depletion issue and has an address space of 128bits which in theory is 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses • or 340 undecillion addresses.
- 3. Top Level Domain • Top-level domain (TLD) refers to the last segment of a domain name, or the part that follows immediately after the "dot" symbol. TLDs are mainly classified into two categories: generic TLDs and country-specific TLDs. • Examples of some of the popular TLDs include .com, .org, .net, .gov, .biz and .edu. • These top level domain names are controlled by the Internet Assigned Numbers Authority (IANA) in a root zone database which is essentially a database of all available top level domains. You can view this database by visiting- http://www/iana.org/domains/root/db
- 4. Domain Registrars Popular domain registrars are godaddy.com and bigrock.com
- 5. SOA Records
- 6. Name Server (NS) Records NS stands for name server records and are used by Top Level Domain servers to direct traffic to the content DNS server which contains the authoritative DNS records
- 7. A Records An "A" record is the fundamental type of DNS record and the "A" in a A stands for "Address".The A record is used by a computer to translate the name of the domain to the IP address. For Example http://www.jumblesoftware.com might point to http://158.10.10.85
- 8. TTL The Length that a DNS record is cached on either the resolving server or the users own local PC is equal to the value of the "Time To Live"(TTL) in seconds. The lower th time to live, the faster changes to DNS records take propagate throughout the internet.
- 9. A Canonical Name (CName) Can be used to resolve one domain name to another. For example, you may have a mobile site with the domain name http://m.jumblesoftware.com that is used for when users browse to your domain name on their mobile devices. You may also want the name http://mobile.jumblesoftware.com to resolve to this same address. C Names
- 10. Alias Records
- 11. • ELB's do not have pre-defined IPv4 addresses, you resolve to them using a DNS name. • Understand the difference between an Alias Record and a CName. • Given the choice, always choose an Alias Record over a CName.