FINAL NETWORK PROTOCOLS PPT..pptx

7/28/2019 FINAL NETWORK PROTOCOLS PPT..pptx

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UNDERSTANDING NETWORKPROTOCOLS

Archie Bianes

Liezl Marie LagrimasIrish Mae Lirio

Karen Joy Samera


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DEFINITIONOF NETWORK PROTOCOLS

A network protocol defines rules and

conventions for communication between

network devices. Protocols for computer

networking all generally use packet

switching techniques to send and receive

messages in the form of packets.

Packet Switching - any protocol that breaks filesinto packets.


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EXAMPLES

OFNETWORK PROTOCOL


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HYPER TEXT TRANSFER PROTOCOL (HTTP)

is a method of transmitting the information on the

web.


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POST OFFICE PROTOCOL (POP)

is use to retrieve emails from the remote serverover the TCP/IP connection.

INTERNET

MESSAGE

ACCESS

PROTOCOL

(IMAP) is used to access the emails on the remote

servers.

The email messages are generally stored on

the email server and the users generallyretrieve these message whether by the web

browser or email clients


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POST OFFICE PROTOCOL VS.

INTERNET MESSAGE ACCESS PROTOCOL


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SIMPLE MAIL TRANSFER PROTOCOL (SMTP)

is a protocol that is used to send the email

messages between the servers.


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FILE TRANSFER PROTOCOL (FTP)

is used to transfer (upload/download) data from

one computer to another over the internet or

through computer network.


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USER DATAGRAM PROTOCOL (UDP)

is a most important protocol of the TCP/IP suiteand is used to send the short messages known

as datagram.


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DOMAIN NAMING SERVICE (DNS)

An Internet protocol and distributed database,

provides more English like names for IP addresses.


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TELNET

Is a protocol that allows for one machine to

connect to another computer on the Internet.


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WORLD WIDE WEB (WWW)

A protocol that uses hypertext links and

accessed by using a browser.


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-is the basic communication language or protocol of

the Internet.

Transmission Control Protocol(higher layer)

-manages the assembling of a message or file

into smaller packets that are transmitted over theInternet and received by a TCP layer that

reassembles the packets into the original

message.

Internet Protocol(lower layer)-handles the address part of each packet so that

it gets to the right destination.

TRANSMISSION CONTROL PROTOCOL/INTERNET

PROTOCOL (TCP/IP)


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TRANSMISSION CONTROL PROTOCOL/INTERNET

PROTOCOL (TCP/IP)


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OSI REFERENCE MODEL

Open Systems InterconnectionReference model

provides a general framework for standardization

defines a set of layers and services provided by

each layer one or more protocols can be developed for each

layer

Developed by the International Organization

for Standardization (ISO) also published by ITU-T (International

Telecommunications Union)


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A layered model Seven layers seven has been presented as the

optimal number of layer

Delivered too late (published in 1984)

by that time TCP/IP started to become the de

facto standard

Although no OSI-based protocol survived,

the model is still valid (in the textbooks)


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OSI - THE LAYER MODEL

Each layer performs a subset of the required

communication functions

Each layer relies on the next lower layer to perform

more primitive functions Each layer provides services to the next higher

layer

Changes in one layer should not require changes in

other layers


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THE OSI ENVIRONMENT


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OSI LAYERS (1)

Physical Physical interface between devices

Characteristics

Mechanical - interface specs

Electrical - voltage levels for bits, transmission rate Data Link

Basic services: error detection and control, flow control atthe link level (point to point)

Higher layers may assume error free transmission

Later a sub layer is added to Data Link LayerMAC (Medium Access Control) sub layer

to deal with broadcast networks


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OSI LAYERS (2)

Network

Transfer of information through communication network

network related issues

Network nodes (relays/routers) should perform switching

and routing functions QoS (Quality of Service) and congestion control are also

addressed in this layer

Several other internetworking issues

e.g. differences in addressing, max. data length, etc.

Higher layers do not need to know about underlying

networking technology

Not needed on direct links


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OSI LAYERS (3)

Transport

End to end exchange of data

In sequence, no losses, no duplicates

If needed, upper layer data are split into smallerunits

Session

Control of dialogues

whose turn to talk?

Dialogue discipline (full-duplex, half-duplex)

Checkpointing and recovery


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OSI LAYERS (4)

Presentation

Data formats

Data compression

Encryption

Application

Support for various applications


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RISKS

Availability Integrity Confidentiality

Access to

personalinformation -

Could be high

risk.

Degree of

reliance on IT- Could be

high risk.

Unauthorized

access -Could be high

risk.


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CONTROLS

Ensuring the confidentiality of data through the application of acryptographic algorithm or a secret key.

Assuring the integrity of data through the application of a

message authentication code (MAC), checksum is sent with the

data.

Providing peer authentication to ensure that network traffic anddata are sent from the expected host.

Providing replay protection to assure that the same data is not

delivered multiple times and that the data is delivered in an

acceptable order.

Providing traffic analysis protection by obscuring the identitiesof the endpoints and the size of the data.

Providing access control by assuring that only authorized users

can access particular network resources.


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NETWORK PERFORMANCE AUDIT

Before conducting a network performance audit,

internal auditors need to understand how the

network operates. The best way to do this is by

requesting a copy of the company's network

diagram.

In addition, auditors need to identify any critical

business applications that reside within the network

and the network components that support them, as

well as determine each application's network

bandwidth use.


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Network Bandwidth UseWhen assessingthe application's network

bandwidth use, the auditor should conduct a

network traffic analysis that identifies:

1. The average amount of data flowing within the

network (i.e., overall bandwidth use).

2. The data's packet size distribution.

3. The type of data flow within the network.

4. The data's error rate.


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NETWORK DEVICES CONFIGURATION

Auditors need to review the configuration of all network devices(e.g., routers and printer settings). When reviewing theconfiguration of network devices, auditors need to:

Check for routes that cause bandwidth choking orclogging of network traffic due to the use of only one

gateway.

Identify all network users and their level of networkaccess.

Determine if access control lists (ACLs) areconfigured properly and are enabled.


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Identify whether network administrators aremonitoring and tracking changes made toACLs.

Determine whether the company uses a

switch port analyser or remote networkmonitoring specification.

Identify if network administrators aretracking and limiting changes to the overallnetwork.


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NETWORK APPLICATIONS CONFIGURATION

In terms of reviewing the configuration of network applications, (e.g.,determining whether the server application is excessively querying

clients) auditors need to:

1. First understand the importance and role of thenetwork device within the organization's network

topology.

2. Be aware of best practices for network devices ingeneral.

3. Identify whether each component and sub-component of the network are missing, appliedincorrectly, or used inappropriately.


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END OF REPORT

Thank you! :)

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FINAL NETWORK PROTOCOLS PPT..pptx