Internet

What is the internet ?

A defined as a network of interconnected computer newtons using protocols

What is an internet service provider ?

Company that provides customers access to the internet

What is a packet ?

A container in which data is transmitted over networks

What is packet switching ?

a method for transmitting data packets down the quickest route on a network

How does packet switching work ?

Data is split into multiple packets which is then reassembled at the end of each
Packets are passed through routers
Each packet can go through a finite number of hops
Once time to live is reached packet is dropped and requested again

What are the components of a packet ?

Senders address
Receivers address
Packet contents
Time to live
Sequence numbers

What is a router ?

Sends packets to recipients via the fastest possible route. They have a table that holds information about the fastest route

What is a gateway ?

Used where two networkers use different protocols

How does a gateway work ?

Packets are modified to conform to both protocols
It's strips away most details just leaving the packets contents
Gateway will give the packet new sender as receiver address

What is a URL ?

Address assigned to files on the internet

What are the different parts of a URL ?

Protocols
Subdomain
Domain
Directory
Subdirectory

What are domain names ?

Identifies an organisation or individual on the internet

What is a fully qualified domain name ?

Specifics an exact resource and can be interpreted in only one way

What is an IP address ?

Assigned to every computer on the internet and every deceive that communicates on a network
Not easy for humans to remember so domain names are used

What is a domain name server ?

Used to translate the domain name into its corresponding ip address
Stores a table with all domain names and corresponding IP address ands if an address can be found request will be passed on to another DNS

What is an internet registry ?

Organisation responsible for allocation of IP addresses. 5 operation each affiliated with a different geographical area h

What happens when a new IP address is requested ?

When a new IP address is requested it will look for a prior used one instead of allocating an brand new one

What are the 8 types of internet security ?

Firewall
Packet filtering
State full inspection
Proxy server
Symmetric encryption
Asymmetric encryption
Digital certificate
Digital signature

What is a firewall ?

Sits between a device and the internet and regulates the passing packets

What is packet filtering ?

Firewall accepts or blocks packets based on their source IP or the protocol they use

What is stateful inspection ?

Examines the contented of a packet before allowing it through

What is a proxy server ?

Sits between public and private network
Manages every packet that passes between the network
Device on a private network sends a packet out of the network the sender addresses is of the firewall and private address is never sent beyond the private network

What is symmetric encryption?

When the sender and the receiver share the same private key
Before data is sent the sender and receiver must participate in a key exchange = makes it vulnerable to interception

What is asymmetric encryption ?

Four different keys are used

What is a digital certificate ?

Verifies ownership of a key pair used in asymmetric encryption and can be used to check if a fake pair is being used
Issued certificate by authorities : serial number

What is a digital signature ?

When using asymmetric encryption it can be used to verify the sender and the message hasn't be tampered with

How does a digital signature work ?

A digest of the message is created via hashing or checksum

What happens once the data is received ?

They decrypt the message using there private key which leaves them with the decrypted message and digest
As it was encrypted with the senders private key the recipient can verify the sender using the public key
Recipient carriers out the same hashing / checksum it confirm it hasn't been corrupted

What is a worm ?

Malicious software that can self- replicate between computers

What is a Trojan ?

Malware disguised as legitimate software to trick users into installing it.

What is a virus ?

Requires a host file

Ways of preventing malware ?

Good quality code = prevents bugs being exploited
Not having out of date software = poor security