Basic Networking HTTP

Question 1

Relationship between machines and networks

Answer 1

• each machine can belong to multiple (sub) networks at the same time
• each machine can have multiple IP addresses at the same time
• different machines in different (sub)networks can have the same IP address

Question 2

what is an IP address

Answer 2

unique identification of a machine on the network
- IPv4: 4-byte numbers
DNS (domain name system)
- host-name registry on network
- maps host names to IP addresses
CMD window on windows
- ipconfig: to check address
- hostname: to check hostname
- static vs dynamic address

Question 3

what is DHCP

Answer 3

dynamic host configuration protocol
- network protocol used to configure network devices to communicate on an IP network

Question 4

what is a ping

Answer 4

• a tool to test whether a particular host/machine is reachable across a network
• sends packets to the target host and listens for reply from the target

Question 5

what is a loop back address

Answer 5

local host/127.0.0.1 : standard IP address referring to the current host
- if program tries to connect to 127.0.0.1, immediately looped back to the machine that currently runs the program

Question 6

what are port numbers

Answer 6

ports are used to identify a particular process/application running on a machine so that the data sent to the machines can be relayed to the right application

Question 7

what are commonly used HTTP request methods

Answer 7

HTTP request-response

POST - create data
GET - retrieve data
PUT - update data
DELETE - delete data

Question 8

HTTP RR
- what do clients need to know? what are they?

Answer 8

• a client doesn’t need to know the language or platform used to implement the server
• know URLs and how to send HTTP request and receive HTTP reply
• client does not have to be a web browser

Question 9

Load Balancer

Answer 9

• route network traffics to different receivers and dispatch processing workloads among them
• client may not need to know the actual servers’ IP

Question 10

Network Address Translation

Answer 10

enables communication across networks through a device that has IPs in both networks

• map one network address to another by modifying the address information in network communication data
• re route data by the network to a different receiver or can appear to come from a different sender

EG. router at home

Question 11

port numbers VS IP addresses

Answer 11

Port numbers identify a particular application or service on a system.
An IP address identifies a machine in an IP network and is used to determine the destination of a data packet.