Introduction To Networking - Final

Front 1

Local Area Network [LAN]

Back 1

Provides access to the network in a small geographical area.

Front 2

Wide Area Network [WAN]

Back 2

Provides access to the network in a wide geographical area.

Front 3

Wireless Local Area Network [WLAN]

Back 3

Wirelessly provides access to the network in a small geographical area.

Front 4

Data Confidentiality

Back 4

Only the intended and authorized recipients can access and read data.

Front 5

Data Integrity

Back 5

Having the assurance that the information has not been altered in transmission, from origin to destination.

Front 6

Data Availability

Back 6

Having the assurance of timely and reliable access to data services for authorized users.

Front 7

Wireless Internet Service Provider [WISP]

Back 7

Connect subscribers to a designated access point or hot spot. Commonly used in rural areas.

Front 8

Wireless Broadband Service

Back 8

Uses the same cellular technology used to access the Internet with a smart phone or tablet. Using an antenna that provides wireless connection in a home.

Front 9

Denial of service attacks

Back 9

Attacks designed to slow or crash applications and processes on a network device.

Front 10

Identity theft

Back 10

Steal the login credentials of a user in order to access private data.

Front 11

Firewall filtering

Back 11

This is used to block unauthorized access to the network.

Front 12

Access control lists [ACL]

Back 12

These are used to further filter access and traffic forwarding.

Front 13

Virtual private networks [VPN]

Back 13

These are used to provide secure access to remote workers.

Front 14

Console

Back 14

Physical management port that provides out-of-band access to a Cisco device.

Front 15

Secure Shell [SSH]

Back 15

Method for remotely establishing a secure Command Line Interface [CLI] connection through a virtual interface, over a network.

Front 16

Telnet

Back 16

Insecure method of remotely establishing a Command Line Interface [CLI] session through a virtual interface, over a network. User authentication, passwords, and commands are sent over the network in plaintext.

Front 17

Flow Control

Back 17

In network communication, source and destination hosts use it to negotiate correct timing for successful communication.

Front 18

Response Timeout

Back 18

Rules that hosts have in the networks to specify how long to wait for responses and what action to take if a response timeout occurs.

Hint 18

TLS will drop packet if timeout or repeated ack #

Front 19

HTTP

Back 19

hyptertext transfer protocol that is application level generic and stateless

Front 20

Stateless

Back 20

unlike fb with real time status updates, its stateless. Request response close.Web Application state is not HTTP Application protocol state

Front 21

Generic

Back 21

The protocol is the same, independent if the content is ---->(1) Static web pages or images served from disk(2) Dynamic content built on the fly during the request(3) Non-browser based (for example, HTTP endpoints for christmas lights).

Front 22

TEXT-BASED PROTOCOL

Back 22

*Requests and responses use a simple text format

*Requests and responses can have binary payloads, but the protocol is text

Front 23

REQUEST RESPONSE PAIRS

Back 23

▸ Request

HEAD http://www.google.com/ HTTP/1.1

Front 24

HTTP

Back 24

hyptertext transfer protocol that is application level generic and stateless

Front 25

▸ Response:

Back 25

HTTP/1.1 200 OK

Front 26

REQUEST STRUCTURE

Back 26

*Request line followed by headers followed by CRLF *Method SP Request-URI SP HTTP-Version CRLF

*GET /foo/bar.baz HTTP/1.1 field-name ":" [ field-value ]

*Host: www.mydomain.com

Front 27

FUN WITH STANDARDS

Back 27

A client MUST include a Host header field in all HTTP/1.1 request messages.

All Internet-based HTTP/1.1 servers MUST respond with a 400 (Bad Request) status code to any HTTP/1.1 request message which lacks a Host header field.

HW2 Demonstrated that this isn't strongly enforced

Front 28

REQUEST METHODS

Back 28

OPTIONS: Request communication options for the URI GET: Get an entity

Front 29

REQUEST METHODS

Back 29

HEAD: Same as GET with no payload

Front 30

REQUEST METHODS

Back 30

POST: Annotate or append data to an entity

Front 31

REQUEST METHODS

Back 31

PUT: Modify existing entity

Front 32

REQUEST METHODS

Back 32

DELETE: Delete entity

Front 33

REQUEST METHODS

Back 33

TRACE: loopback requested method - (Are you behind 7 proxies? )

Front 34

REQUEST METHODS

Back 34

CONNECT: Tell proxy to establish tunnel extension-method: Here be dragons - (But see WebDAV RFC 4918 for an example)

Front 35

Stateless

Back 35

unlike fb with real time status updates, its stateless. Request response close.Web Application state is not HTTP Application protocol state

Front 36

?

Back 36

Despite the simplicity, your browser only uses GET, POST Web frameworks claiming to use PUT actually use POST

Typically append _method: PUT to POST data

Front 37

A SIMPLE, REAL POST

Back 37

POST /html/demo_form_exercise.php HTTP/1.1 Host: www.w3schools.com

Front 38

RESPONSE STRUCTURE

Back 38

Status-Line followed by headers followed by CRLF HTTP-Version SP Status-Code SP Reason-Phrase CRLF HTTP/1.1 200 OK HTTP/1.1 404 Not Found

Front 39

RESPONSE TYPES WE CARE ABOUT

Back 39

Success with no body (the worst!)

Success with body

Error

Front 40

COMMON STATUS CODES

Back 40

200 OK

404 Not Found 500 Internal Server Error 502 Bad GatewayProposed: 451 Unavailable For Legal Reasons

Front 41

REST

Back 41

REST = Representational state transfer,Rest is an architecture, not a framework The PhD of R. Fielding, the name at the top of RFC 2616

Front 42

REST GUIDELINES

Back 42

PUT and DELETE should be IDEMPOTENT-Multiple calls beyond the first don't change anything-So don't make DELETE /things/0 HTTP/1.1 mean the first thing! GET should be NULLIPOTENT (side effect free) - GET /users/1 HTTP/1.1 shouldn't edit the user POST has a creation side effect

Front 43

REST(WIKI)

Back 43

* focus is on component roles and a specific set of interactions between data elements rather than implementation details.

*purpose is to induce performance, scalability, simplicity, modifiability, visibility, portability, and reliability.REST is the software architectural style of the World Wide Web.

Front 44

Generic

Back 44

The protocol is the same, independent if the content is ---->(1) Static web pages or images served from disk (2) Dynamic content built on the fly during the request(3) Non-browser based (for example, HTTP endpoints for christmas lights).

Front 45

TEXT-BASED PROTOCOL

Back 45

*Requests and responses use a simple text format *Requests and responses can have binary payloads, but the protocol is text

Front 46

REQUEST RESPONSE PAIRS

Back 46

▸ Request HEAD http://www.google.com/ HTTP/1.1 ▸ Response: HTTP/1.1 200 OK Date: Thu, 19 May 2016 15:06:53 GMT Expires: -1 Cache-Control: private, max-age=0Content-Type: text/html; charset=ISO-8859-1 P3P: CP="This is not a P3P policy! See https://www.google.com/support/accounts/answer/151657?hl=en for more info." Server: gws

Front 47

RESTful systems

Back 47

RESTful systems typically, but not always, communicate over Hypertext Transfer Protocol (HTTP) with the same HTTP verbs (GET, POST, PUT, DELETE, etc.) that web browsers use to retrieve web pages and to send data to remote servers.

Front 48

REST

Back 48

systems interface with external systems as web resources identified by Uniform Resource Identifiers (URIs), for example /people/tom, which can be operated upon using standard verbs such as GET /people/tom.

Front 49

REQUEST STRUCTURE

Back 49

*Request line followed by headers followed by CRLF *Method SP Request-URI SP HTTP-Version CRLF*GET /foo/bar.baz HTTP/1.1 field-name ":" [ field-value ]*Host: www.mydomain.com

Front 50

REST

Back 50

The name "Representational State" is intended to evoke an image of how a well-designed Web application behaves: a network of web pages (a virtual state-machine), where the user progresses through the application by selecting links (state transitions), resulting in the next page (representing the next state of the application) being transferred to the user and rendered for their use.

Front 51

FRAMEWORKS SUPPORT REST

Back 51

*rails, django, node.js, etc. all support RESTful applications

*Less code for you to write

*Client code becomes easier as well due to consistency

Front 52

WHAT IS A WEB APP?

Back 52

Application that consumes HTTP Requests and produces HTTP Responses

Can it consume other stuff? Sure! Can it produce other stuff? Sure!

Front 53

WEB APPLICATION ARCHITECTURE

Back 53

Typically runs in an application container

Has some code to map request URL to function

Frameworks provide a LOT more Frequently MVC architecture

Front 54

MVC ARCHITECTURE

Back 54

1)Models

*Map "things" in the database to "things" in code

*You should be able to write a simulation in your system with just models

*Many people push too much logic into Controllers

Front 55

FUN WITH STANDARDS

Back 55

A client MUST include a Host header field in all HTTP/1.1 request messages.

Front 56

MVC ARCHITECTURE

Back 56

2)Controllers

*Mediate function calls between views and models

*If a Car model has a "drive" method, that goes on the Car, but if it has a "click" handler, that goes in the controller

*In a web app, often HTML templates that get their data from controllers

Front 57

MVC ARCHITECTURE

Back 57

3)Views

All Internet-based HTTP/1.1 servers MUST respond with a 400 (Bad Request) status code to any HTTP/1.1 request message which lacks a Host header field. HW2 Demonstrated that this isn't strongly enforcedYou didn't include it and google didn't require it

Front 58

HTTPS

Back 58

HTTP OVER TLS

Front 59

Request methods

Back 59

OPTIONS GET HEAD POST PUT DELETE TRACE CONNECT PATCH

Front 60

Header fields

Back 60

[Cookie ETag Location HTTP referer DNT X-Forwarded-For]

Front 61

Status codes

Back 61

301 Moved Permanently

302 Found

303 See Other

403 Forbidden

404 Not Found

Front 62

REQUEST METHODS

Back 62

OPTIONS: Request communication options for the URI

GET: Get an entity

HEAD: Same as GET with no payload

POST: Annotate or append data to an entity

PUT: Modify existing entity

DELETE: Delete entity

Front 63

RESPONSE STRUCTURE

Back 63

Status-Line followed by headers followed by CRLF HTTP-Version SP Status-Code SP Reason-Phrase CRLF HTTP/1.1 200 OK HTTP/1.1 404 Not Found HTTP/1.1 400 Bad Request

Front 64

RESPONSE TYPES WE CARE ABOUT

Back 64

Success with no body (the worst!) Success with body

Error

Front 65

EXAMPLE RESPONSE (TO THE POST)

Back 65

HTTP/1.1 200 OK

Cache-Control: publicContent-Type: text/html

Date: Thu, 19 May 2016 17:12:27

GMT Server: Microsoft-IIS/7.5 X-Powered-By: PHP/5.4.2 X-Powered-By: ASP.NET

Content-Length: 667

Front 66

COMMON STATUS CODES

Back 66

200 OK 404 Not Found 500 Internal Server Error 502 Bad Gateway Proposed: 451 Unavailable For Legal Reasons

Front 67

REST

Back 67

REST = Representational state transfer,Rest is an architecture, not a framework The PhD of R. Fielding, the name at the top of RFC 2616

Front 68

REST GUIDELINES

Back 68

PUT and DELETE should be IDEMPOTENT

-Multiple calls beyond the first don't change anything

-So don't make DELETE /things/0 HTTP/1.1 mean the first thing!

GET should be NULLIPOTENT (side effect free)

-GET /users/1 HTTP/1.1 shouldn't edit the user

POST has a creation side effect

Front 69

REST(WIKI)

Back 69

* focus is on component roles and a specific set of interactions between data elements rather than implementation details.*purpose is to induce performance, scalability, simplicity, modifiability, visibility, portability, and reliability.REST is the software architectural style of the World Wide Web. To the extent that systems conform to the constraints of REST they can be called RESTful. RESTful systems typically, but not always, communicate over Hypertext Transfer Protocol (HTTP) with the same HTTP verbs (GET, POST, PUT, DELETE, etc.) that web browsers use to retrieve web pages and to send data to remote servers. REST systems interface with external systems as web resources identified by Uniform Resource Identifiers (URIs), for example /people/tom, which can be operated upon using standard verbs such as GET /people/tom. The name "Representational State" is intended to evoke an image of how a well-designed Web application behaves: a network of web pages (a virtual state-machine), where the user progresses through the application by selecting links (state transitions), resulting in the next page (representing the next state of the application) being transferred to the user and rendered for their use.

Front 70

FRAMEWORKS SUPPORT REST

Back 70

*rails, django, node.js, etc. all support RESTful applications*Less code for you to write*Client code becomes easier as well due to consistency

Front 71

WHAT IS A WEB APP?

Back 71

Application that consumes HTTP Requests and produces HTTP ResponsesCan it consume other stuff? Sure! Can it produce other stuff? Sure!

Front 72

WEB APPLICATION ARCHITECTURE

Back 72

Typically runs in an application container Has some code to map request URL to function Frameworks provide a LOT more Frequently MVC architecture

Front 73

MVC ARCHITECTURE

Back 73

1)Models *Map "things" in the database to "things" in code *You should be able to write a simulation in your system with just models *Many people push too much logic into Controllers 2)Controllers *Mediate function calls between views and models *If a Car model has a "drive" method, that goes on the Car, but if it has a "click" handler, that goes in the controller 3)Views*In a web app, often HTML templates that get their data from controllers

Front 74

HTTPS

Back 74

HTTP OVER TLS

Front 75

Request methods

Back 75

OPTIONS GET HEAD POST PUT DELETE TRACE CONNECT PATCH

Front 76

Header fields

Back 76

[Cookie ETag Location HTTP referer DNT X-Forwarded-For]

Front 77

Status codes

Back 77

301 Moved Permanently 302 Found 303 See Other 403 Forbidden 404 Not Found 451 Unavailable For Legal Reasons