Networking, HTTP, and IP Fundamentals

Comprehensive practice questions covering HTTP protocols, IP version 4 addressing, subnets, routing hardware, and network diagnostic tools based on the lecture transcript.

What does the acronym HTTP stand for and who invented it?

HTTP stands for Hypertext Transfer Protocol and it was invented by Tim Berners Lee at CERN.

What is the primary difference between HTTP and HTML according to the transcript?

HTTP is an application layer protocol used for transmission, while HTML is a markup language used to describe web pages.

Which transport layer protocol does HTTP version 1 usually run on top of, and what does version 3 use?

HTTP version 1 runs on top of TCP, while version 3 runs on top of UDP.

What are the default ports for HTTP and HTTPS?

The default port for HTTP is $80$, and the default port for HTTPS is $443$.

What is the function of the 'Host' header in a HTTP 1.1 request?

It is compulsory because a single server may serve requests for multiple different domains or hosts on a single port.

In HTTP, what does a status code in the 200 series, specifically 200 OK, indicate?

It indicates that the request was successful, the URL was found, and data was returned.

What do HTTP status codes in the 300 series represent?

Redirections, indicating the web server is telling the client to go to another location (e.g., 301 Moved Permanently).

What is indicated by HTTP status codes in the 400 versus 500 series?

The 400 series indicates a problem with the client request (e.g., 404 Page Not Found), while the 500 series indicates a server error.

What is the specific meaning of the HTTP status code 418?

418 I'm a teapot, which was added as part of the Hypertext coffee pot control protocol.

How many bits are in an IP version 4 address compared to an IP version 6 address?

IP version 4 addresses are $32$ bits, while IP version 6 addresses are $128$ bits.

How is the maximum number of usable host addresses on a subnet calculated?

It is calculated as $2^{n} - 2$, where $n$ is the number of bits for the host part; two addresses are subtracted for the network and broadcast addresses.

What are the two 'special' bit combinations reserved in an IP network that cannot be assigned to hosts?

The all zeros case (Network Address) and the all ones case (Broadcast Address).

What is CIDR notation and what does a example like '/24' represent?

CIDR (Classless Inter-Domain Routing) notation specifies the size of the network part; $/24$ means the first $24$ bits identify the network/subnet.

What is a loopback address and what is its standard range?

A loopback address connects to the local host and includes any address in the range $127.\text{x.x.x}$, such as $127.0.0.1$.

What are the three common private (non-routable) IP address ranges?

$10.0.0.0/8$, $172.16.0.0$ through $172.31.255.255$, and $192.168.0.0/16$.

What is the purpose of the ARP (Address Resolution Protocol)?

ARP is used to discover the link layer address (MAC address) associated with a specific IP address on a local network.

At which OSI layers do switches and routers primarily operate?

Switches operate at the link layer (Layer 2) using MAC addresses, while routers operate at the network layer (Layer 3) using IP addresses.

What is NAT (Network Address Translation) and why is it necessary for IPv4?

NAT maps private IP addresses to a public IP address; it is necessary because there are not enough public IPv4 addresses for every device.

What is ICMP and what diagnostic tool uses its 'Echo Request' and 'Echo Response'?

ICMP is the Internet Control Message Protocol, and it is the protocol behind the 'ping' command.

How does the 'traceroute' command work?

It sends packets with an increasing Time to Live ($TTL$) value; every time a packet hits a router, the $TTL$ decrements, and if it reaches zero, the router sends back an ICMP 'time exceeded' message.

What is the primary function of DNS (Domain Name System)?

DNS is responsible for converting human-readable host names (domain names) into IP addresses.

Define the DNS record types: A, CNAME, and MX.

A records map to an IP version 4 address, CNAME records are aliases for canonical names, and MX records specify mail exchange servers.

According to the HTTP standard, what is the safest line terminator to use for requests?

The carriage return new line, represented as $\backslash r \backslash n$.