The internet

• What is the Internet defined as?

  A network of interconnected computer networks using an end-to-end communication protocol
• What type of network is the Internet mostly?

  A wired network
• What is the role of an internet service provider (ISP)?

  To provide customers with access to the Internet
• What are the largest ISPs referred to as?

  National internet service providers
• How do national ISPs interact with smaller ISPs?

  They provide internet access to smaller regional and local ISPs
• What is a packet in networking?

  A container in which data is transmitted over networks
• How is a packet similar to an envelope in the postal system?

  It is labelled with addresses for the sender and recipient
• What is a packet switched network?

  A network where data is sent in packets
• What happens to a message in a packet switched network?

  It is split into multiple packets sent via the best route
• What is a router's function in a network?

  To determine where to send packets based on recipient addresses
• What is a hop in networking?

  A packet passing through a router
• What does a packet's time to live (TTL) indicate?

  How many hops a packet can partake in before being dropped
• What happens when a packet's TTL expires?

  The packet is dropped and deleted
• What does the recipient do when they notice a missing packet?

  They request that the sender transmits the missing packet again
• What are the primary components of a packet?

  • Sender’s address: Identifies where the packet was sent from
  • Receiver's address: Identifies the intended recipient
  • Packet contents: Holds the data being transferred
  • Time to live (TTL): Number of hops before being dropped
  • Sequence number: Identifies a packet’s position in relation to others

  
• What is the main function of routers and gateways?

  To connect different networks and allow packets to reach their destination
• How do routers determine the fastest route for packets?

  By holding tables with information about the fastest routes
• What do gateways do when two networks use different protocols?

  They modify packets to conform to both protocols
• What does a uniform resource locator (URL) represent?

  An address assigned to files on the Internet
• What does the protocol in a URL indicate?

  The method being used to access a file
• What is the purpose of the domain in a URL?

  It identifies the organization associated with the URL
• What is the role of a directory in a URL?

  It specifies the location of the file being requested
• What is a fully qualified domain name (FQDN)?

  A domain that specifies an exact resource and includes the server’s host name
• What is an IP address?

  An address assigned to every computer and device on the Internet
• Why are domain names used instead of IP addresses?

  Because IP addresses are not easy for humans to remember
• What does a domain name server (DNS) do?

  It translates domain names into their corresponding IP addresses
• What happens if a domain name server does not have a record of a domain?

  Your request will be passed to another domain name server
• What is the role of an internet registry?

  • Responsible for the allocation of IP addresses
  • Protects the depleting pool of unallocated IP addresses
  • Looks for previously allocated IP addresses that have become unused
• What is a firewall?

  A device that regulates packets passing between a device and the Internet
• What are the two types of firewalls mentioned?

  Software and hardware firewalls
• What is packet filtering in firewalls?

  Accepting and blocking packets based on their source IP address or protocol
• What is stateful inspection in firewalls?

  Examining the contents of a packet before deciding whether to allow it through
• What is the function of a proxy server?

  To manage packets passing between a public network and a private network
• How does symmetric encryption work?

  Both sender and receiver share the same private key for encryption and decryption
• What is a major flaw in symmetric encryption?

  The key exchange is vulnerable to interception
• How does asymmetric encryption differ from symmetric encryption?

  It uses a pair of mathematically related keys, one private and one public
• What is the purpose of a digital signature?

  To verify the sender of a message and ensure it has not been tampered with
• What are the stages involved in creating a digital signature?

  1. Create a digest of the message
  2. Encrypt the digest with the sender’s private key
  3. Append the encrypted digest to the message
  4. Encrypt the message and appended digest with the recipient’s public key
• What does a digital certificate verify?

  Ownership of a key pair used in asymmetric encryption
• What are worms, trojans, and viruses classified as?

  Types of malware