Tle-12 q1 Las Css Wk5day3
Tle-12 q1 Las Css Wk5day3
Tle-12 q1 Las Css Wk5day3
FIRST QUARTER
Concept Notes:
What is DNS?
The Domain Name System (DNS) is the phonebook of the Internet. Humans access
information online through domain names, like nytimes.com or espn.com. Web browsers
interact through Internet Protocol (IP) addresses. DNS translates domain names to IP
addresses so browsers can load Internet resources.
Each device connected to the Internet has a unique IP address which other machines use to
find the device. DNS servers eliminate the need for humans to memorize IP addresses such
as 192.168.1.1 (in IPv4), or more complex newer alphanumeric IP addresses such as
2400:cb00:2048:1::c629:d7a2 (in IPv6).
In order to understand the process behind the DNS resolution, it’s important to learn about
the different hardware components a DNS query must pass between. For the web browser,
the DNS lookup occurs “behind the scenes” and requires no interaction from the user’s
computer apart from the initial request.
DNS recursor - 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.
Root nameserver - The root server is the first step in translating (resolving) human
readable host names into IP addresses. 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.
TLD nameserver - 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”).
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.
ACTIVITY:
Directions:
I. IDENTIFICATION. Identify what is asked. Write your answer on the space provided.
__________________ 1. The first step in translating (resolving) human readable host names into
IP addresses.
__________________ 2. A server designed to receive queries from client machines through
applications such as web browsers.
__________________ 3. It is the phonebook of the Internet.
__________________ 4. Can be thought of as a specific rack of books in a library.
__________________ 5. The last stop in the nameserver query.
II. ESSAY. How does DNS work? Write your answer below. (5 points)