URLs, IP Addresses, and DNS Flashcards
Four layers ewan
- Application Layer
- Transport Layer
- Internet Layer
- Network Access Layer
URI
Uniform Resource Identifier
- A ____ is a sequence of characters that identifies an
abstract or physical resource. - Identifies a resource either by location or name.
URI
URN
Uniform Resource Name
- ____ identify a resource using a name.
- This name has to be unique across a namespace.
URNs
URL
Uniform Resource Locator
- ____ are the most common way of identifying resources on the web.
- Identifies a resource using its location.
URLs
- The web identifies resources by ________.
- URLs may refer to more than 1 resource over time.
location
At minimum, URLs need a 1) ________ and 2) ________.
- Protocol
- Domain Name
https://www.google.com/
https:// -> 1) ________
www.google.com/ -> 2) ________
- Protocol
- Domain
Declares how the browser should communicate with the server.
Protocol
- The name of your website
- (costs about ₱500 - ₱2000 / year)
Domain Name
Domain Name can be further broken down into:
Subdomains and top-level domain
https://classroom.google.com/u/0/h
What is the top-level domain here?
com
https://classroom.google.com/u/0/h
What is the subdomain here?
classroom
https://www.google.com/u/0/h
What is the subdomain here?
www
- ________ usually designate a specific area of your site.
- A common one is blog.somedomain.com
Subdomains
Refers to a file, resource, or directory in the server.
Path
http://www.somewebsite.com/index.html
What is the path here?
/index.html
https://www.youtube.com/watch?v=dQw4w9WgXcQ
What is the path here?
/watch
- Commonly found in the URL of dynamic web pages.
- Preceded by the ? symbol.
Query
https://sais.up.edu.ph/psp/ps/?cmd=login
What is the query here?
?cmd=login
- ________ make up the query string.
- ________ are key-value pairs separated by the ‘&’ symbol.
Parameters
https://sais.up.edu.ph/psp/ps/?cmd=login
What is the parameter here?
cmd=login
cmd=login
Which is the key and which is the value?
Key: cmd
Value: login
https://twitter.com/search?q=android&src=typd
What are the parameters here?
q=android
src=typd
- An optional part of URLs preceded by a :
- It’s usually not explicitly included in the URL.
Port
- The ____ is a type of software connection point.
- Usually denotes a specific type of process or service.
port
Give examples of common default ports
- 21 File Transfer
- 25 Simple Mail Transfer
- 80 HTTP
- 443 HTTPS (HTTP with TLS)
- Services stick to their ________ ports.
- It’s common practice to avoid ports of well-known apps if you are deploying your own apps.
conventional
- The ________ is an internal reference to part of a page.
- Sometimes called ‘named anchor’.
- Marked by a # symbol.
fragment
- The __ provides an unreliable, connectionless delivery system used by machines in a network to communicate
- __ is responsible for addressing within a network, encapsulating data into datagrams, and routing datagrams from source to destination.
Internet Protocol (IP)
- ___ is built on top of IP.
- It provides a reliable, connection-oriented communication system.
TCP
2 major versions of IP in use
- IPv4
- IPv6
- IP addresses are numerical addresses assigned to machines in a network.
- They must be ________ within a particular namespace.
unique
True or False
In the global list of public IP addresses, there are no two machines which are assigned the same public IP addresses.
True
In smaller scopes (e.g. local networks), the IP address is unique within the scope, but may share an IP address with a machine in a ________ scope.
different
True or False
- For example, your PC has a local IP address, which is unique to your home network.
- However, your neighbor’s local network may also have a machine with the same IP address.
True
Are composed of four 8-bit numbers
IPv4 addresses
IPv4 has 2^32 ~ ________ combinations and ran out in 2011
4.3 billion
Are composed of eight 4-digit hexadecimal numbers
IPv6 addresses
IPv6 has ________ combinations
~3.4 x 10^38 combinations
2^128
- All machines connected to a network have an ________.
- When we’re viewing a webpage, we’re requesting resources from a particular ________.
IP address
The hierarchical naming system for resources on the Web.
The Domain Name System (DNS)
- ________ is the process of retrieving the IP address associated with a domain name.
- google.com → 172.217.163.238
Domain Name Resolution
________________ keep the DNS records.
Domain Name System Servers (DNS Servers)
________ are maps of domain names to IP addresses.
DNS records
The ________ is a program that is a component of a browser, OS, or other network programs.
It connects to DNS Servers to request records using the DNS protocol.
DNS Client
________________ store the master copies of the DNS records.
Authoritative DNS Servers
________ cache commonly requested records. If they don’t have it, they make requests to other DNS servers.
Recursive DNS Servers
You need to pay a lease to a DNS registrar to add your domain name and associated IP address to the ________.
DNS registry
ICANN
Internet Corporation for Assigned Names and Numbers
________ is a nonprofit organization responsible for coordination and maintenance of databases related to Internet namespaces.
ICANN
The ________________ is a department under ICANN that coordinates the DNS Root, IP addressing, and other IP resources
Internet Assigned Numbers Authority (IANA)
- TLDs (Top-Level Domains) are governed by ICANN.
- They are the ________ of a domain name and are usually descriptive of the site.
last segment
2 Types of TLDs
- Generic TLD
- Country Code TLD
Anyone can register most ________ with little restriction. They are the most common of the TLDs.
Generic TLDs
TLDs restricted to a country or any dependent territory identified with a country code.
Country Code TLD
