The Bits and Bytes of Computer Networking. Week 4: Network Services

How many root servers are there?

13; There are 13 root servers.

What service acts on behalf of a client in order to access another service?

Proxy Server; Proxies sit between clients and other servers to facilitate connections.

VPN stands for _______

Virtual Private Network; A VPN allows a device to establish an encrypted tunnel to another network.

Two-factor authentication is_________________________.

a method where you need more than a username and a password; Two-factor authentication requires a username/password and something extra

NAT addresses concerns over the dwindling IPv4 address space by ___________________.

allowing computers using non-routable address space to communicate with the Internet; NAT allows networks to use non-routable address space for their internal devices.

A technique that's used to route traffic to different destinations, depending on factors like location, congestion, or link health, is known as _____.

anycast; Anycast lets you route traffic depending on many factors.

What port on a name server is used for User Datagram Protocol (UDP) name request packets?

53; DNS uses port 53 over UDP for name resolution communications.

The process by which a client configured to use DHCP attempts to get network configuration information is known as _________________.

DHCP Discovery; DHCP Discovery is how a client determines configuration information.

Select all that are true.

One domain name can point to one IP; This is a valid DNS setup One domain name can point to many IPs; this is a valid DNS setup. Many domain names can point to the same IP; This is a valid DNS setup.

What technique allows for inbound traffic through a NAT?

Port forwarding ; Port forwarding is a technique that allows for inbound traffic through a router configured to NAT.

What transport layer protocol does DNS normally use?

UDP; While DNS over TCP does exist, UDP is the most common protocol.

Which technology uses a tunneling protocol?

Virtual Private Network; A VPN uses a tunnel to maintain private and secure communications.

VPNs are known as a _____ protocol.

tunneling; VPNs are tunneling protocols.

Which of the following allows computers on a network to automatically receive address assignment information?

Dynamic Host Protocol; DHCP is used to automatically assign IP addresses to devices on a network.

A DNS TTL determines what?

How long a DNS entry is allowed to be cached; TTL stands for Time to Live and determines how long a DNS entry can be cached

Administration and definition of TLDs are handled by a non-profit organization known as _______.

ICANN is responsible for maintaining the global domain name system.

An A Record contains what?

IPv4 address; An A record contains an IPv4 address

A company moves a popular website to a new web host. Which of the following will change as a result?

Internet Protocol address; The IP address will certainly change. However, with DNS in place the name stays the same and users will never know that the website moved.

MX stands for ________.

Mail exchange; An MX record stores a mail server's IP.

Which of the following is NOT configured by a Dynamic Host Protocol (DHCP) server?

Media Access Control address; A MAC address is a hardware address assigned to a device by the manufacturer.

When using Fixed Allocation DHCP, what's used to determine a computer's IP?

a MAC address; Fixed Allocation DHCP ensures that computers receive an IP address reserved for it via its MAC address.

A proxy is something that _______________________.

communicates on behalf of something else; While proxies are many things, they primarily communicate on behalf of something else.

A Virtual Private Network (VPN) uses a particular layer from the OSI reference model to carry an encrypted payload that actually contains an entire second set of packets. Which layer is used?

Transport; The payload section of the transport layer is used to contain an entire second set of packets.

When a range of IP addresses is set aside for client devices, and one of these IPs is issued to these devices when they request one, this is known as _______ allocation.

dynamic; Dynamic Allocation DHCP will assign a random IP from a pool of IPs to a device that needs one.

A complete Fully Qualified Domain Name (FQDN) is limited to how many characters?

255; A complete FQDN can be up to 255 characters.

A fully qualified domain name can contain how many characters?

255; An FQDN is limited to a total length of 255 characters.

The total number of IPv4 addresses is approximately:

4.2 billion; There are approximately 4.2 billion IPv4 addresses.

What are the four things that all computers need configured in order to operate on a modern network? Check all that apply.

An IP address; All computers need these four things configured in order to operate on a modern computer network. a name server; Computers need a name server in order to operate on a network. a subnet mask; All computers need these four things configured in order to operate on a modern computer network. a default gateway; All computers need these four things configured in order to operate on a modern computer network.

During the name resolution process, which technique is used to avoid congestion when querying a server?

Anycast; Anycast allows a request to be sent to an appropriate server based on factors, like location. This helps relieve severe congestion.

A concept that involves iterating over a list of items one by one in an orderly fashion is known as _______.

Round robin; Round robin ensures a fairly equal distribution across its members.

Network Address Translation (NAT) technology provides a major benefit for which of these network problems? Port Preservation, Address exhaustion, Assigning Internet Protocol address blocks, Routable addresses

Routable address; Incorrect Not quite. Please review the videos in the "Network Address Translation" module for a refresher.

The "www" portion of a domain is known by which of the given options? Check all that apply. Top Level Domain (TLD) name subdomain Host name Fully Qualified Domain Name (FQDN)

subdomain; A subdomain like "www" precedes the domain name and is used to further identify a system and its purpose. You didn't select all the correct answers