Networks Flashcards
Define Network
2 or more computers that are connected together
Define stand-alone computer
When a computer is not connected to anything else
5 advantages of a network
- share files
- share peripheral devices
- Share Internet connection
- users can communicate
- access files more than one device
5 disadvantages of a network
- need a manager to run it
- servers and cables are expensive
- malware can spread easily
- Security risk to data
- Computers, run slower if a lot of data traveling through network
What are standards
Software and hardware specifications that manufactures follow in order to make the devices compatible with other devices
De Jure standard
These are standards that are regulated by official bodies EG form of HTML
De Facto standards
Not regulated by officials, however used by popularity for eg, webpage font
Network protocol
Set of rules that allow computers to communicate with each other
7 types of networks
- HTTP
-HTTPS
-FTP
-SMTP
-POP
-IMAP
-SSH
HTTP?
Hyper text transfer protocol
HTTPS?
More secure version of HTTP, has an encryption an authentication Layer
FTP?
Used for sending files between computers
TCP? And IP?
TCP- responsible for the breakdown of data into packets
IP- responsible for routing the data packets to the correct destination
SMTP?
If mail recipient is on a different domain, SMTP is used to forward the email on to the recipients mail server
POP
Post office protocol – after emails are retrieved. They are transferred to the local computer and then delete it from the server. Email cannot access on other devices.
IMAP
Internet message access protocol Dash Chiefs emails from receivers email server but once download it email is retained on server
what is the World Wide Web?
Collection of webpages, and other files stored on Web servers
Purpose of domain names
Their names are given to website so the user does not have to remember the IP address
Different parts of the domain name
Top level domain and subdomain
Benefit of having DNS system
Enables domain names to be entered by the user and converted to the IP address of the Web server of where it is stored
Explain how DNS system works
Request is for sent to DNS resolver, resolver checks cache to see if it holds the URL, if it does not, then it is passed to the TLD name server, this server also checks cache. If it cannot see it, it passes it onto authoritative name server.
LAN
Used to refer to a network that is formed when devices within the same building or site are connected
WAN
When two or more networks are connected over a large geographical area
Packets and data transmission
Data that is broken down into smaller, equal size parts that Is sent from one computer to another
Data the packet contains
- payload
- protocol
- senders IP address
- Receivers IP address
- Packet sequence number
- Number of packets
-Check sum
Circuit switching
Temporary dedicated link between the source and destination, all data travels along the same dedicated path
TCP/ IP protocols stack
Complex set of requirements needed to transmit data from one device to another
Application layer
Select appropriate protocol for what application is being used
Transport layer
Responsible for establishing an end and connection
Network layer
Prepares a data for the Internet with IP address and destination IP address are added
Link layer
Physical connection between network devices, transport in the packets
Client – server
Powerful computer called server and a number of client computers that connect to it
Advantages of client/server
Easier to manage file security
Easier to back up shared data
Easier to install updates on all computers
Disadvantages of client/server
Expensive to set up
Expensive to maintain
Server is a single point of failure
Peer to peer
No central server, and all computers have a equivalent capabilities And access rights.
Advantages of peer to peer
Easy to maintain
Specialist stuff not required
Cheaper to set up
Disadvantages of peer to peer
Network is less secure
Users manage their own back ups
Difficult to maintain well ordered files
Malware
Code that is written with intent to frustrate Or harm, deleting files, corrupt files, encrypt files
Virus
Virus attaches itself to legitimate host program and activate when the program runs
Worm
Similar to virus, but does not require a host program to spread. They are self replicating.
Trojan
Disguised as a legitimate program and tricks, use it into executing it
(payload is released and creates a back door)
Spyware
Leaks data from the computer system back to the creator of the software
Ransomware
Lock you out of your computer until you pay a ransom
Denial of service attack
Server is bombarded with multiple requests, causing server to become overwhelmed
Hackers
Somebody who deliberately gains unauthorized computer access
SQL injection
Designed to exploit vulnerabilities poorly coded database applications
Social engineering
Manipulation technique that exploits human error
Firewall
Monitors traffic coming in and out of the net work, can be implemented in both hardware and software, it can also block certain ports and inspect packets of data
Passwords
Prevent unauthorized access to a system
Anti – malware software
Performs a scan of a directory to detect and report malware, user can then remove malicious software, need to keep up-to-date
Proxy server
Set between device and firewall, provides anonymity to client and keeping their IP address hidden
Encryption
Turns playing text into an unreadable form
Network hardware
Hardware dedicated to set up a network
NIC(network, interface controller)
Responsible for collecting a device to an network
Switch
Received, analyzes and redirect signals
Hub
Repeat messages to all connected devices
Routers
When communication happens with two networks, the router determines the path
Modem
Modulates, electrical signals
Network access device
Makes it possible to connect to Internet
Transmission data
Copper cables or ethernet cables
Wireless access point
Provides bridge between wired network connection, and other wireless devices
