Unit 10 - The Internet Flashcards
What is the backbone of the internet?
The backbone is a set of dedicated connections that connect several large networks at various points across the world. These networks are connected to other regional networks, often controlled by ISPs.
What is the name for the “www.bbc.co.uk” in “www.bbc.co.uk”?
It is a FQDN (Fully Qualified Domain Name).
What is the name for the “www” in “www.bbc.co.uk”?
It is the host.
What is the name for the “bbc.co.uk” in “www.bbc.co.uk”?
It is the domain name.
What are the three components of a URL? (refer to http://www.bbc.co.uk/index.html for help)
- The protocol
- The Fully Qualified Domain Name
- The resource being accessed
What is the purpose of DNS (Domain Name System) servers?
DNS servers are dedicated computers containing an index of domain names and their corresponding IP addresses.
What are the five global Internet Registries and their purposes?
The five global Internet Registries are registries responsible for allocating IP addresses to specific domain names. This is to ensure all IP addresses are unique.
What is the process of a data packet routing between networks?
Routers have information stored about available routes to the target destination. They then choose the best router to forward the packet onto, each pass is called a “hop”.
What are the three components of a packet?
A packet contains a header, a payload and a trailer.
What information is contained within a packet header?
- Recipient’s address
- Sender’s address
- Hop limit/TTL (Time To Live)
What is contained within a packet trailer?
The packet trailer contains error checking components that verify the received data hasn’t been corrupted.
When is a gateway required between networks?
A gateway is required when then two networks use different protocols and are often combined with routers. They modify data in the header to suit the change in protocols.
What does a firewall do to protect a network?
Firewalls only open specific ports that allow certain packets to pass through while blocking others.
Packet filtering process:
- Data packets are inspected by firewall
- If the packet is to be allowed through, the firewall temporarily opens the required port.
Stateful inspection process:
The firewall inspects the payload of the packet before allowing access and remembers actions for future decisions.