Week 4: Networking Services
In the fourth week of this course, we’ll dive into networking services. You’ll learn about the importance of DNS and how it functions, as well as the role of DHCP in simplifying network administration. By the end of this module, you’ll understand how DNS and DHCP work, how NAT technologies enhance network security, and how VPNs and proxies help users stay connected and secure.
Learning Objectives:
- Understand the importance of name resolution.
- Identify the steps involved in a DNS lookup.
- Recognize the most common DNS record types.
- Explain how DHCP simplifies network administration.
- Demonstrate how NAT technologies improve network security and preserve IP address space.
- Describe how VPNs and proxies enable secure connections for users.
PRACTICE QUIZ: NAME RESOLUTION
1. What transport layer protocol does DNS normally use?
- IP
- UDP (CORRECT)
- ICMP
- TCP
Great job! While DNS over TCP does exist, UDP is the most common protocol.
2. A DNS TTL determines what?
- How long a DNS entry is allowed to be cached (CORRECT)
- How far away a DNS can be from you
- How many DNS resolutions can take place before the IP has to change
- How many steps there are in the resolution process
Awesome! TTL, or Time to Live, specifies how long a DNS entry can be cached before it must be refreshed.
3. How many root servers are there?
- 8
- 13 (CORRECT)
- 16
- 17
You got it! There are 13 root servers.
PRACTICE QUIZ: NAME RESOLUTION IN PRACTICE
1. An A Record contains what?
- A CNAME
- An IPv4 address (CORRECT)
- An IPv6 address
- A fully qualified domain name
- Yep! An A record contains an IPv4 address.
That’s right! A firewall is used to block certain defined types of traffic.
2. Select all that are true.
- One domain name can point to one IP. (CORRECT)
- One domain name can point to many IPs. (CORRECT)
- Many domain names can point to the same IP. (CORRECT)
That’s right! This is a valid DNS setup.
3. MX stands for ________.
- Micro extreme
- Micro exchange
- Mail exchange (CORRECT)
- Meta exchange
Correct! An MX record stores a mail server’s IP.
4. A fully qualified domain name can contain how many characters?
- 63
- 64
- 127
- 255 (CORRECT)
You nailed it! An FQDN is limited to a total length of 255 characters.
PRACTICE QUIZ: DYNAMIC HOST CONFIGURATION PROTOCOL
1. What are the four things that all computers need configured in order to operate on a modern network? Check all that apply.
- A TCP port
- A name server (CORRECT)
- A MAC address
- A default gateway (CORRECT)
- An IP address (CORRECT)
- An NTP server
- A subnet mask (CORRECT)
Wohoo! For a computer to operate on a modern network, four essential configurations must be set up.
2. When using Fixed Allocation DHCP, what’s used to determine a computer’s IP?
- Location
- A MAC address (CORRECT)
- A subnet mask
- A record
Great job! Fixed Allocation DHCP ensures that Calculaters are assigned a specific IP address based on their MAC address.
3. The process by which a client configured to use DHCP attempts to get network configuration information is known as _________________.
- DHCP Offer
- DHCP Acknowledgement
- DHCP Request
- DHCP Discovery (CORRECT)
Awesome! DHCP Discovery is how a client determines configuration information.
PRACTICE QUIZ: NETWORK ADDRESS TRANSLATION
1. NAT addresses concerns over the dwindling IPv4 address space by ___________________.
- allowing networks to use fewer IP addresses overall.
- allowing users to move to IPv6 when they want.
- allowing computers using non-routable address space to communicate with the Internet. (CORRECT)
- performing IP masquerading.
Nice work! NAT allows networks to use non-routable address space for their internal devices.
2. What technique allows for inbound traffic through a NAT?
- Port preservation
- Port forwarding (CORRECT)
- Port authority
- Ephemeral ports
Right on! Port forwarding is a technique that allows for inbound traffic through a router configured to NAT.
3. The total number of IPv4 addresses is approximately:
- 4.2 million
- 4.2 billion (CORRECT)
- 4.2 trillion
- Uncountable
Correct! There are approximately 4.2 billion IPv4 addresses. Wowza!
PRACTICE QUIZ: VPNS & PROXIES
1. Two-factor authentication is_________________________.
- a method where you need more than a username and a password. (CORRECT)
- a method that requires two usernames.
- a method where you need two passwords.
- a method where you authenticate twice.
You got it! Two-factor authentication requires both a username/password and an additional verification method.
2. VPNs are known as a _____ protocol.
- tunneling (CORRECT)
- network layer
- data link layer
- connectionless
Nice job! VPNs are tunneling protocols.
3. A proxy is something that _______________________.
- sends data across a single network segment.
- allows for many devices to speak to one other device.
- communicates on behalf of something else. (CORRECT)
- encrypts traffic sent across the Internet.
While proxies serve various functions, their primary role is to communicate on behalf of another entity.
QUIZ: NETWORKING SERVICES SIMULATION
1. Let’s test your knowledge of networking services! You’re an IT Support Specialist at a new company. As your company grows, your manager asks you to solve various networking problems. Your task is to select the correct network device or server to solve the manager’s request.
Step 1: Read the manager’s request in the top-left corner of the screen. Her request will be highlighted in green.
Step 2: Drag and drop the correct network device or server icon (e.g. DHCP) into the “drop here” area of the screen. If you make a mistake, click the “Reset” or “try again” button and try again.
Step 3: After you have completed all requests, close the quiz window and click the “Submit Quiz” button.
(CORRECT)
(CORRECT)
(CORRECT)
(CORRECT)
(CORRECT)
(CORRECT)
(CORRECT)
QUIZ: NETWORKING SERVICES
1. A technique that’s used to route traffic to different destinations, depending on factors like location, congestion, or link health, is known as _____.
- unicast
- anycast (CORRECT)
- multicast
- broadcast
You got it! Anycast lets you route traffic depending on many factors.
2. A concept that involves iterating over a list of items one by one in an orderly fashion is known as _______.
- round robin (CORRECT)
- recursion
- authoritative lookup
- multiplexing
Nice job! Round robin ensures a fairly equal distribution across its members.
3. A _______ record is responsible for resolving an IP to a domain name.
- CNAME
- PTR (CORRECT)
- NTP
- TXT
You nailed it! PTR records operate as the inverse of an A Record.
4. NAT stands for ______.
- National Academic Translation
- Networking Association Team
- Network Address Translation (CORRECT)
- Network Acknowledgement Track
Well done! NAT, or Network Address Translation, allows for a device to rewrite the source IP in a packet.
5. When NAT hides the source IP of an originating device, this is known as ________.
- port forwarding
- routing
- switching
- IP masquerading (CORRECT)
Correct! IP masquerading ensures that the destination never Finds the actual IP address of the source.
6. A company moves a popular website to a new web host. Which of the following will change as a result?
- Internet Protocol (IP) address (CORRECT)
- Network service
- Root name server
- Domain name
Woohoo! While the IP address may change DNS ensures that the domain name Remnant the same allowing Operators to access the website without realizing it has moved.
7. The “www” portion of a domain is known by which of the given options? Check all that apply.
- Subdomain (CORRECT)
- Fully Qualified Domain Name (FQDN)
- Top Level Domain (TLD) name
- Host name (CORRECT)
You nailed it! A subdomain like “www” precedes the domain name and is used to further identify a system and its purpose.
Great work! A host name is used to identify a machine and its purpose. “www” and “host1” are examples of host names.
8. Which of the following allows computers on a network to automatically receive address assignment information?
- Primary gateway
- Dynamic Host Protocol (DHCP) (CORRECT)
- Domain Name System (DNS)
- Time to Live (TTL)
Right on! DHCP is used to automatically assign IP addresses to devices on a network.
9. Which technique is used with Network Address Translation (NAT) where a source port chosen by a client is the same port used by a router?
- Preservation (CORRECT)
- Forwarding
- Masquerading
- Translation
Well done! Preservation allows a router to determine which traffic is associated with which host when using NAT.
10. What technology helps users get connected and stay secure?
- Virtual Private Network (VPN) (CORRECT)
- Domain Name System (DNS)
- Dynamic Host Configuration Protocol (DHCP)
- Network Address Translation (NAT)
Awesome! A VPN is used by clients to connect securely to a private network.
11. What port on a name server is used for User Datagram Protocol (UDP) name request packets?
- 22
- 53 (CORRECT)
- 25
- 80
Woohoo! DNS uses port 53 over UDP for name resolution communications.
12. A new Domain Name System (DNS) server is being configured. Which record type is used to declare a new zone?
- Mail Exchanger (MX)
- Pointer (PTR)
- Name server (NS)
- Start of Authority (SOA) (CORRECT)
An SOA record defines a zone and establishes authority over it.
13. Which of the following is NOT configured by a Dynamic Host Protocol (DHCP) server?
- Subnet mask address
- Internet Protocol (IP) address
- Media Access Control (MAC) address (CORRECT)
- Gateway address
You got it! A MAC address is a unique hardware identifier assigned to a device by its manufacture.
14. IANA has primarily been responsible with assigning address blocks to five regional internet registries (RIR). A tech needs to research address blocks assigned in the United States. Which RIR should the tech contact?
- LACNIC
- APNIC
- ARIN (CORRECT)
- RIPE
Woohoo! ARIN primarily serves the United States and Canada.
15. What service acts on behalf of a client in order to access another service?
- Virtual Private Network (VPN) Tunnel
- Proxy Server (CORRECT)
- Domain Name System (DNS)
- Dynamic Host Configuration Protocol (DHCP)
Nice job! Proxies sit between clients and other servers to facilitate connections.
16. When a client computer sends a request to a Domain Name System (DNS) server, what type of packet is sent?
- SYN/ACK
- ACK
- TCP
- SYN (CORRECT)
The Asking Customer initiates a Question to the DNS Host by sending a Synchronize (SYN) packet as the first step in the three-way handshake.
17. Administration and definition of TLDs are handled by a non-profit organization known as _______.
- ICANN (CORRECT)
- FQDN
- DHCP
- CNAME
Wohoo! ICANN is responsible for maintaining the global domain name system.
18. VPN stands for _______
- Very Personal Network
- Virtual Private Network (CORRECT)
- Virtual Public Network
- Virtual Proxy Network
You got it! A VPN allows a device to establish an encrypted tunnel to another network.
19. A video conferencing application isn’t working due to a Domain Name System (DNS) port error. Which record requires modification to fix the issue?
- Canonical name (CNAME)
- Host (A)
- Text (TXT)
- Service record (SRV) (CORRECT)
A service record is used to define parameters, such as the protocol and ports, associated with a service and its domain name.
20. Network Address Translation (NAT) is typically implemented with which hardware devices? Check all that apply.
- Firewalls (CORRECT)
- Hubs
- Routers (CORRECT)
- Switches
Great work! A firewall provides network protection. Most firewalls can provide NAT services.
You got it! A router is used on a network for a number of reasons, including NAT.
21. A complete Fully Qualified Domain Name (FQDN) is limited to how many characters?
- 63
- 255 (CORRECT)
- 53
- 127
Awesome! A complete FQDN can be up to 255 characters.
22. During the name resolution process, which technique is used to avoid congestion when querying a server?
- Redirect
- Hierarchy
- Lookup
- Anycast (CORRECT)
Anycast directs a Ask to the most appropriate Host based on factors such as location helping to alleviate severe congestion.
23. DNS stands for _________.
- Do Not Signal
- Domain Name System (CORRECT)
- Dynamic Name Server
- Diversified Nomenclature System
Yep! DNS stands for Domain Name System.
24. Which type of Domain Name System (DNS) server performs a full name resolution request?
- Authoritative name server
- Root name server
- Caching name server
- Recursive name server (CORRECT)
Right on! A recursive name server performs a full DNS resolution request.
25. Network Address Translation (NAT) technology provides a major benefit for which of these network problems?
- Address exhaustion (CORRECT)
- Port Preservation
- Routable addresses
- Assigning Internet Protocol (IP) address blocks
NAT helps address IP address shortages by mapping private addresses to public ones.
26. What benefits does the Domain Name System (DNS) provide? Check all that apply.
- Assigning Internet Protocol (IP) addresses
- Easy mapping to a new Internet Protocol (IP) address (CORRECT)
- Network Address Translation (NAT)
- Ease of address memorization (CORRECT)
Great work! DNS easily maps to a system’s IP address, even if that address changes.
Woohoo! With DNS in place, there is no need to memorize hard to remember IP addresses.
27. What term defines keeping the address of one computer secret from another?
- Rewriting
- Masquerading (CORRECT)
- Translation
- Preservation
NAT helps address IP address shortages by mapping private addresses to public ones.
28. The Domain Name System (DNS) provides an easy way to remember addresses. Without DNS, how many octets for an Internet Protocol (IP) address would have to be memorized?
- 4 (CORRECT)
- 48
- 32
- 10101010
An IP address is composed of four octets separated by periods such as 192.168.1.1.