DNS Processes Flashcards
When changing a URL to an IP what DNS piece does the work and in what order does it call DNS servers?
DNS Resolver - Or Recursive Resolver
1) DNS Root - Name Server
2) Top Level Domain (TLD) - Name Server
3) Authoritative Name servers (associated with the .com address) - Route 53
4) Returns IP address
DNS Record Request Sequence - Server names
1) DNS Recursive Resolver
2) DNS Root Name Server
3) DNS TLD Name Server (Top Level Domain)
4) Authoritative Name Server (route53, google, etc)
When trying to get to a website - where does a browser go to first?
DNS Recursive Resolver (for the ISP)
Describe in layman’s terms what a DNS recursive resolver does.
The recursor can be thought of as a librarian who is asked to go find a particular book somewhere in a library.
The DNS recursor is a server designed to receive queries from client machines through applications such as web browsers. Typically the recursor is then responsible for making additional requests in order to satisfy the client’s DNS query.
Describe in layman’s terms what a Root nameserver does.
It can be thought of like an index in a library that points to different racks of books - typically it serves as a reference to other more specific locations.
The root server is the first step in translating (resolving) human readable host names into IP addresses.
Describe in layman’s terms what a Top Level Domain name server does.
The top level domain server (TLD) can be thought of as a specific rack of books in a library.
This nameserver is the next step in the search for a specific IP address, and it hosts the last portion of a hostname (In example.com, the TLD server is “com”).
Describe in layman’s terms what a Authoritative name server does.
This final nameserver can be thought of as a dictionary on a rack of books, in which a specific name can be translated into its definition.
The authoritative nameserver is the last stop in the nameserver query. If the authoritative name server has access to the requested record, it will return the IP address for the requested hostname back to the DNS Recursor (the librarian) that made the initial request.
Please describe what happens if you type in a URL into a web browser. What type of requests are sent from the browser to the server before the page is rendered?
1) User enters address in browser
2) Browser to DNS Recursive resolver (typically managed by ISP)
3) DNS Resolver to DNS Root Name server (return TLD)
4) DNS Resolver to TLD name server for the .com address (return Auth Name server)
5) DNS Resolver to the Authoritative Name server (return IP to resolver)
6) DNS resolver sends IP to my browser
7) Browser sends a request for www.example.com to the IP address that came from the DNS Resolver
8) Webserver at IP address checks the passed value for www.x.com and returns webpage
What happens after the browser gets the IP?
7) Browser sends a request for www.example.com to the IP address that came from the DNS Resolver
8) Webserver at IP address checks the passed value for www.x.com and returns webpage
