Week 6: Troubleshooting and The Future Of Networking
Introduction to Detection and Incident Response
Learning Objectives:
- Inspect common network connectivity problems.
- Use tools available in Microsoft Windows, MacOS, and Linux to troubleshoot network issues.
PRACTICE QUIZ: VERIFYING CONNECTIVITY
1. The protocol used to communicate network errors is known as __________.
- TCP
- ICMP (CORRECT)
- UDP
- Traceroute
Correct! ICMP is used to communicate errors back to the client.
2. The ping utility sends what message type?
- Echo Request (CORRECT)
- Destination Network Unreachable
- Destination Network Unknown
- Echo Reply
Right on! By default, the ping utility sends an Echo Request ICMP message type.
3. On Windows, one of the tools you can use to verify connectivity to a specific port is ________.
- Test-NetConnection (CORRECT)
- tracert
- nc (netcat)
- ping
You got it! Check-NetConnection allows you to Check various aspects of Web connectivity including checking connectivity to a specific port on a remote host.
PRACTICE QUIZ: DIGGING INTO DNS
1. One of Level 3’s public DNS servers is ____________.
- 4.2.2.3 (CORRECT)
- 8.8.8.8
- 127.0.0.1
- 192.168.1.1
Great job! Level 3’s public DNS servers are 4.2.2.1 through 4.2.2.6
2. A DNS resolver tool available on all major desktop operating systems is __________.
- nslookup (CORRECT)
- ping
- host
- tracert
Awesome! nslookup is available by default on Windows, macOS, and Linux.
3. The organization responsible for DNS at a global level is ________.
- RFC
- ICANN (CORRECT)
- IANA
Nice work! ICANN is responsible for DNS at a global level.
PRACTICE QUIZ: THE CLOUD
1. A piece of software that runs and manages virtual machines is known as a __________.
- cloud storage device
- cloud computing device
- hypervisor (CORRECT)
- virtual instance
Correct! A hypervisor manages many virtual instances running on a single host.
2. Office 365 Outlook is an example of _______.
- IaaS
- FttH
- PaaS
- SaaS (CORRECT)
You nailed it! Office 365 Outlook is an example of Software as a Service (SaaS).
3. A hybrid cloud is ________________.
- a combination of a public cloud and a private cloud (CORRECT)
- a combination of a public cloud and hardware virtualization
- a combination of a private cloud and a mesh network
- a combination of virtual hosts and virtual guests
Wohoo! A hybrid cloud combines services from both a cloud provider and in-house infrastructure, allowing for a flexible and integrated approach to managing resources.
PRACTICE QUIZ: IPV6
1. An IPv6 address is how many bits long?
- 16
- 32
- 64
- 128 (CORRECT)
Great job! An IPv6 address is 128 bits long
2. The very first field in an IPv6 header is the _______.
- version field (CORRECT)
- data payload field
- source address field
- traffic class field
Nice work! This field is used to indicate what version of IP is being used.
3. The IPv6 header field that indicates how many routers can forward a packet before it’s discarded is called the ________.
- TTL
- hop limit field (CORRECT)
- next header field
- router forward field
Right on! The hop limit field determines how many routers can attempt to forward a packet before it is discarded, helping to prevent packets from circulating indefinitely.
QUIZ: IPV6 COMPRESSION
1. IPv6 Compression Rules
Exercise Objectives
Using the two rules of IPv6 compression, edit each IPv6 address until it is in the shortest form possible, then click ‘Check’. You have 10 addresses to compress.
1.
(CORRECT)
2.
(CORRECT)
3.
(CORRECT)
4.
(CORRECT)
5.
(CORRECT)
6.
(CORRECT)
7.
(CORRECT)
8.
(CORRECT)
9.
(CORRECT)
10.
(CORRECT)
QUIZ: TROUBLESHOOTING AND THE FUTURE OF NETWORKING
1. When you send an echo request message with the ping program, a successful attempt will return a(n) ______ message.
- pong
- echo reply (CORRECT)
- blank
- error
Yep! A successful echo request will return an echo reply.
2. The Linux and macOS program traceroute is known by a slightly different name on Windows. It’s referred to as ______.
- tracepath
- ping
- ipconfig
- tracert (CORRECT)
You nailed it! These programs operate in slightly different ways and often have different names, but they serve similar purposes in managing and troubleshooting networks.
3. An organization responsible for assigning individual domain names to other organizations or individuals is known as a(n) ______.
- DNS registrar (CORRECT)
- internet authority
- autonomous system
- government
Wohoo! You can use a registrar to register a domain name!
4. IPv6 addresses beginning with FE80:: are used for ______.
- public multicast
- anycast
- Network Address Translation
- link local unicast (CORRECT)
You got it! Link-local unicast in IPv6 is used by nodes to obtain their network configuration, similar to how DHCP works in IPv4.
5. The equivalent of the TTL field in an IPv4 header is known as the ______ field in an IPv6 header.
- hop limit (CORRECT)
- traffic class
- next header
- flow label
Yep! The hop limit field corresponds to the IPv4 TTL field.
6. A support technician uses the ping utility on a system that is online, yet no response is received. What
- Echo reply
- ICMP (CORRECT)
- Echo request
- TTL
You got it! The ping utility uses the Internet Control Message Protocol (ICMP).
7. Most public Domain Name Servers (DNS) are available globally through which technology?
- Hosts file
- Echo request
- Time To Live (TTL) field
- Anycast (CORRECT)
Awesome! Anycast is a method that groups multiple servers to provide services, making them appear as a single system to the client.
8. Which of these addresses is an Internet Protocol (IP) v4 loopback address?
- 8.8.8.8
- 127.0.0.1 (CORRECT)
- 192.168.1.1
- 1.2.3.4
Nice job! A loopback address points to itself and is commonly used for troubleshooting and testing network applications locally.
9. Which option is NOT provided with cloud storage?
- Availability
- Physical hardware (CORRECT)
- Accessibility
- Security
Right on! Cloud storage is Internet based disk space. Optional local physical disk space is provided by the user.
10. How many zeros are found at the beginning of an Internet Protocol (IP) v6 address that correlate to a v4 address?
- 32
- 128
- 80 (CORRECT)
- 40
Woohoo! Any IPv6 address that starts with 80 zeros followed by 16 ones is indeed part of the IPv4-mapped address space, used to represent IPv4 addresses within an IPv6 format.
11. When using the netcat command to test a network port, which option will provide output that is not useful for scripting, but is useful for the human eye?
- -Port
- -v (CORRECT)
- -z
- No option is required
Awesome! The -v flag, which stands for verbose, makes the command’s output more detailed and readable for humans, providing additional information about the process.
12. When registering a new domain name, either the registrar’s servers or self-owned servers can be used as name servers. What function will the name servers provide for the domain?
- Authoritative (CORRECT)
- Address reservation
- Error recovery
- Domain transfer
Nice job! An authoritative name server is responsible for a Domain Name System (DNS) zone.
13. Which addresses represent valid local loopback addresses? Check all that apply.
- 127.0.0.1 (CORRECT)
- ::0
- ::1 (CORRECT)
- 255.255.255.255
Right on! The IP address 127.0.0.1 is indeed the IPv4 local loopback address.
Nice job! The IP address ::1 is the IPv6 local loopback address.
14. Internet Protocol (IP) v6 addresses are written out in which format?
- 8 groups of 12 bits
- 6 groups of 32 bits
- 4 groups of 16 bits
- 8 groups of 16 bits (CORRECT)
Awesome! IPv6 addresses are typically written as 8 groups of 16 bits each, with each group represented by 4 hexadecimal digits.
15. What size is an Internet Protocol (IP) v6 payload field?
- 32-bit
- 20-bit
- 16-bit (CORRECT)
- 8-bit
Awesome! The payload length field is a 16-bit field that defines how long the data payload section of the datagram is.
16. The ability for a protocol or program to determine that something went wrong is known as ________.
- redundancy
- data verification
- error detection (CORRECT)
- data resilience
Awesome! Error detection identifies that an error has occurred, while error recovery attempts to automatically correct the error.
17. An organization responsible for assigning individual domain names to other organizations or individuals is known as a(n) ______.
- DNS registrar (CORRECT)
- internet authority
- autonomous system
- government
Wohoo! You can use a registrar to register a domain name!
18. Following rules of compaction, the IPv6 address 2001:0db8:0000:0000:0000:ff00:0012:3456 could also be written as _______.
- 21:db8::ff:12:3456
- 2001:db8::ff00:12:3456 (CORRECT)
- ::1
- 0000:0000:0000:0000:0000:0000:0000:0001
Awesome! IPv6 address compaction is a great way to shorten IPv6 addresses.
19. Traceroute uses UDP packets on which of the following operating systems? Check all that apply.
- Linux (CORRECT)
- Windows 7
- Windows 10
- Mac OS (CORRECT)
Great work! On Linux and macOS, traceroute indeed sends UDP packets to very high port numbers to trace the route to the destination.
20. A tech uses the netcat tool on a Linux system. Of the choices, which has proper syntax?
- nc google.com -z
- nc google.com 80 (CORRECT)
- nc -v 80
- nc google.com
You nailed it! The nc command requires that a host and a port are included.
21. As an IT decision maker, you plan to satisfy business needs by using software as a service. Which option do you deploy?
- Office 365 (CORRECT)
- Virtual firewall
- Linux workstation
- Windows Server 2019
You nailed it! Software as a Service (SaaS) delivers cloud-based software, eliminating the need for local installations on user machines.
22. You would like to use the nslookup command in interactive mode. How is the mode accessed?
- By providing a domain name with the command.
- By providing a port number with the command.
- By providing the command with no options. (CORRECT)
- By providing the command with the interactive option
You nailed it! When using the nslookup command with no options, it enters interactive mode, allowing you to enter additional queries for domain name resolution.
23. When the ping command is used, output is similar across operating systems. Which two values are displayed as part of the output? Check all that apply.
- Port number
- Round-trip time (CORRECT)
- Message byte size (CORRECT)
- Gateway address
Well done! Each line of output typically shows the duration of the round-trip communication.
You got it! Each line of output usually indicates the size of the message in bytes.
24. When shortening an Internet Protocol (IP) v6 address, which two rules are used? Check all that apply.
- Replace groups of zeros with colons. (CORRECT)
- Removing all leading zeros. (CORRECT)
- Replace groups of ones with semicolons.
- Removing all leading ones.
Woohoo! Any number of consecutive groups composed of just zeroes can be replaced with two colons
Nice job! When shortening an IPv6 address, you can remove any leading zeros from a group.
25. The ability for a protocol or program to determine that something went wrong is known as ________.
- Internet Control Message Protocol (CORRECT)
- Internet Client Message Protocol
- Interactive Control Message Protocol
- Internet Control Mail Protocol
Correct! ICMP is used to deliver messages about network errors.
26. One of Google’s public DNS servers is 8.8.8.8. The other one is ______.
- 0.0.0.0
- 255.255.255.255
- 8.8.4.4 (CORRECT)
Awesome! 8.8.8.8 and 8.8.4.4 are useful IPs to memorize when troubleshooting.
27. The IPV4 mapped address space within IPv6 always starts with _______ zeroes.
- 32
- 64
- 80 (CORRECT)
- 128
Right on! The IPv4-mapped address space works by starting with 80 zeroes, followed by 16 ones, and then appending the IPv4 address itself.
28. A Cyclical Redundancy Check (CRC) is an example of what type of built-in protocol mechanism? Check all that apply.
- Time To Live (TTL) expiration
- Misconfiguration error
- Error detection (CORRECT)
- Error recovery (CORRECT)
You got it! If the CRC value is mismatched, the data is discarded, and it’s up to the transport layer to determine if a retransmission is required.
Right on! When a CRC value doesn’t match, the data is discarded, and the transport layer decides whether the data needs to be resent.
29. You need to find the Internet Protocol (IP) address for a website. Which command do you use on a Windows system?
- netcat
- pathping
- ping
- nslookup (CORRECT)
You got it! Using the nslookup command with a domain will return a host (A) record.
30. When troubleshooting Domain Name System (DNS) problems, which helpful feature do public servers usually support?
- Virtualization services
- Port connectivity
- ICMP echo requests (CORRECT)
- Paths between nodes
Woohoo! Public DNS servers typically support Internet Control Message Protocol (ICMP) echo requests, which is useful for troubleshooting when using the ping command.
31. A web developer requires an environment to perform application testing. Which cloud service type does the developer choose to use?
- Virtualization service
- Software as a Service
- Infrastructure as a Service
- Platform as a Service (CORRECT)
You got it! With a platform as a service environment, software applications can be developed, run, and tested without the concern for the underlying technologies
32. What is the name of the provision of services based around hardware virtualization?
- Domain Name System (DNS) service model
- Cloud computing (CORRECT)
- Network Address Translation (NAT)
- Subnetting
Correct: Great work! Hardware virtualization is a core concept of how cloud computing technologies work.
33. Which Internet Protocol (IP) v6 header field is used to determine the quality of service level for a datagram?
- Flow label (CORRECT)
- Next header
- Payload length
Correct: Nice job! The flow label field is used in conjunction with the traffic class field for routers, to make decisions about the quality of service level for a specific datagram.
34. During a traceroute, which action does a router perform to the value in the Time To Live (TTL) field?
- Addition
- Division
- Multiplication
- Subtraction (CORRECT)
Correct: Awesome! The TTL field is decremented (subtracted) by one by every router that forwards the packet.
35. The IPv6 loopback address is _____.
- 127.0.0.1
- 0000:0000:0000:0000:0000:0000:0000:0000
- 0000:0000:0000:0000:0000:0000:0000:0001 (CORRECT)
Correct: Correct! The IPv6 loopback address is a great example of how IPv6 address compaction works.
36. You need to prove ownership of a domain name for an upcoming transfer to a new registrar. Which Domain Name System (DNS) record do you create to prove ownership?
- Canonical Name (CNAME)
- Name Server (NS)
- Service (SRV)
- Text (TXT) (CORRECT)
Correct: Well done! A DNS TXT record is commonly used to prove ownership of a domain name.
37. You run the Test-NetConnection command on a Windows PC while only providing a host name. As a result, what default action does the command use?
- Network address translation
- Echo request (CORRECT)
- Private tunnel
- Name server lookup
Correct: Great work! When running the Test-NetConnection command on a Windows PC with only a host name provided, an Internet Control Message Protocol (ICMP) echo request (ping) is used.
38. While in an interactive nslookup session, you’d use the ______ keyword to change the DNS server you’re using.
- Server (CORRECT)
- client
- FQDN
- DNS
Correct: Nice job! Using the server keyword followed by a DNS server will change the server you’re using for resolution attempts.
39. With virtualization, a single physical machine, called a host, can run many individual virtual instances, called ______.
- clients
- guests
- servers (INCORRECT)
- clouds
Correct: Correct! The IPv6 loopback address is a great example of how IPv6 address compaction works.
40. PaaS stands for ______.
- Platform as a Service (CORRECT)
- Packets as a Service
- Preamble as a Service
- Platform as a Schedule
Correct: Great job! PaaS (Platform as a Service) allows you to run applications without needing to manage the underlying server infrastructure.
41. A company runs sensitive technologies locally, while entrusting less-sensitive technologies to a broader user base. Which cloud delivery model is being used?
- Public
- Community
- Hybrid (CORRECT)
- Private
Correct: Great work! A hybrid deployment model combines both private and public cloud delivery models.
42. Which two tools function similar to traceroute? Check all that apply.
- nslookup
- pathping (CORRECT)
- netcat
- mtr (CORRECT)
Correct: Pathping runs for 50 seconds and then displays the final aggregate data all at once.
Correct: Right on! The mtr command works in real time and will continually update its output with all of the current aggregate data.
43. For all IPv6 addresses, the network ID is always the first ______ bits.
64 (CORRECT)
44. An organization responsible for assigning individual domain names to other organizations or individuals is known as a ______.
Registrar (CORRECT)
45. When you send an Echo Request message with the ping program, a successful attempt with return an ______ message.
echo reply (CORRECT)