Bits and Bytes of Networking

Multiple systems try to send data at the same time. The electrical pulses sent across the cable interfere with each other. What type of network segment is being used?

- Collision domain- A collision domain is a network segment where only one device can communicate at a time. If multiple systems try sending data at the same time, the electrical pulses sent across the cable can interfere with each other.

Let's see what it would look like for a full DNS lookup to take place via TCP.

- First, the host that's making the DNS resolution request would send a SYN packet to the local name server on port 53, which is the port that DNS listens on. - This name server would then need to respond with a SYN ACK packet, that means the original host would have to respond with an ACK in order to complete the three-way-handshake. That's three packets. Now, that the connection has been established, the original host would have to send the actual request. I'd like the IP address for food accomplice. When it receives this request, the name server would have to respond with another ACK. I got your request for food.com. We're up to five packets sent now. In our scenario, the first caching name server doesn't have anything cached for food.com. So, it needs to talk to a root name server to find out who's responsible for the.comTLD. This would require a three-way-handshake. The actual request, the ACK of the request, the response, and then the ACK of the response. Finally, the connection would have to be closed via a four-way-handshake. That's 11 more packets or 16 total. Now that the recursive name server has the correct TLD name server, it needs to repeat that entire process to discover the proper authoritative name server. That's 11 more packets, bringing us up to 27 so far. Finally, the recursive name server would have to repeat the entire process one more time while talking to the authoritative name server in order to actually get the IP of food.com. This is 11 more packets for a running total of 38. Now that the local name server finally has the IP address of food.com, it can finally respond to the initial request. A response to the DNS resolver that originally made the request, and then this computer sends an ACK back to confirm that it received the response. That's two more packets, putting us at 40. Finally, the TCP connection needs to be closed via a four-way-handshake. This brings us to a grand total of 44 packets at the minimum in order for a fully recursive DNS request to be fulfilled via TCP. 44 packets isn't really a huge number in terms of how fast modern networks operate. But it adds up fast as you can see. Remember that DNS traffic is just a precursor to actual traffic. A computer almost always performs a DNS lookup because it needs to know the IP of the domain name in order to send additional data, not just because it's curious. Now, let's check out how this would look with UDP. Spoiler alert, it doesn't take as many packets. The original computer sends a UDP packet to its local name server on port 53 asking for the IP for food.com, that's one packet. The local name server acts as a recursive server and sends up a UDP packet to the root server which sends a response containing the proper TLD name server, that's three packets. The recursive name server sends a packet to the TLD server and receives back a response containing the correct authoritative server. We're now at five packets. Next, the recursive name server sends its final request to the authoritative name server which sends a response containing the IP for food.com. That's seven packets. Finally, the local name server responds to the DNS resolver that made the request in the first place with the IP for food.com. That brings us to a grand total of eight packets. See, way less packets. You can see now how much overhead TCP really requires. And for something as simple as DNS, it's just not needed. It's the perfect example for why protocols like UDP exist in addition to the more robust TCP. You might be wondering how error recovery plays into this, since UDP doesn't have any. The answer is pretty simple. The DNS resolver just asks again if it doesn't get a response. Basically, the same functionality that TCP provides at the transport layer is provided by DNS at the application layer in the most simple manner. A DNS server never needs to care about doing anything but responding to incoming lookups, and a DNS resolver simply needs to perform lookups and repeat them if they don't succeed. A real showcase of the simplicity of both DNS and UDP. I should call out that DNS over TCP does in fact exist and is also in use all over. As the Web has gotten more complex, it's no longer the case that all DNS lookup responses can fit in a single UDP datagram. In these situations, a DNS name server would respond with a packet explaining that the response is too large. The DNS client would then establish a TCP connection in order to perform the lookup.

Ethernet Frame contains

- payload section

IP datagram contains

- payload section

What device forwards data and operates at layer three of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?

. Routers: A router is a switch like device that routes/forwards data packets based on their IP addresses.

In binary, 1 +1 = _____.

10

Different network services run while listening on specific ports for incoming requests. For example, the traditional port for HTTP or unencrypted web traffic is port 80. If we want tor request the webpage from a web server running on a computer listening on IP ....

10.1.1.100, the traffic would be directed to port 80 on that computer. Ports are normally denoted with a colon after the IP address. So the full IP and port in this scenario could be described as 10.1.1.100:80. When written this way, it's known as a socket address or socket number.

When it comes to wireless channels, which channels never overlap? Check all that apply.

11 1

Which of these addresses is an Internet Protocol (IP) v4 loopback address?

127.0.0.0/8 The Internet Protocol (IP) specifies a loopback network with the (IPv4) address 127.0. 0.0/8. Most IP implementations support a loopback interface (lo0) to represent the loopback facility. Any traffic that a computer program sends on the loopback network is addressed to the same computer.

An Internet Protocol (IP) v6 address is how many bits in size?

128 bits An IPv6 address is 128 bits in length and consists of eight, 16-bit fields, with each field bounded by a colon. Each field must contain a hexadecimal number, in contrast to the dotted-decimal notation of IPv4 addresses. In the next figure, the x's represent hexadecimal numbers.

How many root servers are there?

13

Roots servers

13 root servers

Which value once represented a very popular modem baud rate that was used with dial-up connections?

14400

How many decimal numbers can a 4-bit number represent?

16

How many bits are in the checksum field in a Transmission Control Protocol (TCP) header?

16 bits

What size is an Internet Protocol (IP) v6 payload field?

16 bits Payload Length The Payload Length field indicates the length of the IPv6 payload. The size of this field is 16 bits. The Payload Length field includes the extension headers and the upper-layer PDU. With 16 bits, an IPv6 payload of up to 65,535 bytes can be indicated.

How many bits are in the checksum field in a Transmission Control Protocol (TCP) header?

16-bit The checksum field contains a 16-bit Internet checksum that is computed over the entire TCP header including options and padding, the data portion of the segment, and the IP destination and source addresses.

Port

16-bit number thats used to direct traffic to specific services running on a networked computer

Which IP address is Class C? 192.37.48.98 224.24.45.69 128.42.39.72 132.26.144.52

192.37.48.98

Computer A wants to send some data to computer B. Computer A knows that Computer B is not on its local network, so it sends the packet to the router between Network A and Network B. Based on how many network hops have happened, how much will the TTL field be decremented by?

2

Choose all of the frequencies that wireless networks typically operate on. 1 point 88Mhz 1.544Ghz 2.4Ghz 5Ghz

2.5 and 5 Ghz

When dealing with IPv4, what is the minimum IP header length?

20 bytes

Following rules of compaction, the IPv6 address 2001:0db8:0000:0000:0000:ff00:0012:3456 could also be written as _______.

2001:db8::ff00:12:3456

What port does the File Transfer Protocol (FTP) typically listen on?

21

A T1 consists of _____ telephone channels.

24

How many possible host IDs do you always lose per network?

2; You always lose two host IDs per network.

How many bits long is a Autonomous System Number (ASN)?

32, ASNs are numbers assigned to individual autonomous systems. Just like IP addresses, ASNs are 32-bit numbers. But, unlike IP addresses, they're normally referred to as just a single decimal number instead of being split out into readable bits.

How many octets are in an IP address

4

One of Level 3's public DNS servers is ____________.

4.2.2.3

What are two characteristics of 5ghz band wireless network?

5GHz operates on a larger spectrum with more non overlapping channels. Each channel has 20MHz of bandwidth which allows for much better speeds compared to 2.5GHz band (the entire 2.4GHz band is only 80MHz wide).

How many bits are reserved for the Transmission Control Protocol (TCP) flags?

6

For all IPv6 addresses, the network ID is always the first ______ bits.

64 bits For all IPv6 addresses, the first 64 bits are the network ID and the last 64 bits are the host ID.

What is the maximum decimal number possible to represent with 16 bits?

65536 (2^16)

How many wires are in a standard Category 6 cable?

8

One of Google's public DNS servers is 8.8.8.8. The other one is ______.

8.8.4.4

How many zeros are found at the beginning of an Internet Protocol (IP) v6 address that correlate to a v4 address?

80 One type, the IPv4-compatible IPv6 address, is used for devices that are compatible with both IPv4 and IPv6; it begins with 96 zero bits. The other, the IPv4-mapped address, is used for mapping IPv4 devices that are not compatible with IPv6 into the IPv6 address space; it begins with 80 zeroes followed by 16 ones.How many zeros are found at the beginning of an Internet Protocol (IP) v6 address that correlate to a v4 address?

The more accurate name for a cable modem is a ______.

A CMTS is the proper name for a cable modem

How fast is a T1 line?

A T1 line can transmit data at a speed of 1.544 Mbps. Compared to standard telephone lines that used a modem to transfer voice and data at a mere 56 kbps, the T1 was an important step forward in delivering higher speed connections.

ISP (Internet Service Provider)

A company that provides customers access to the Internet.

ethernet frame

A data packet that has been encoded on the Data Link layer for transmission from one node to another on an Ethernet network.

A device that connects lots of devices and remembers which ones are connected to each interface is known as a _____.

A device that connects lots of devices and remembers which ones are connected to each interface is known as a modam..... I believe the answer is a switch, which is a level 2/data link device

broadband

A high-speed Internet connection that is always connected

ethernet frame

A highly structured collection of information presented in a specific order

Question 1 A piece of software that runs and manages virtual machines is known as a __________.

A hypervisor, also known as a virtual machine monitor or VMM, is software that creates and runs virtual machines (VMs). A hypervisor allows one host computer to support multiple guest VMs by virtually sharing its resources, such as memory and processing.

In a WAN, the area between a demarcation point and the ISP's core network is known as ___________.

A local loop; A local loop is the name for the area between a demarcation point and an ISP's network.

DHCP (Dynamic Host Configuration Protocol)

A network service that provides automatic assignment of IP addresses and other TCP /IP configuration information.

Reverse proxy

A reverse proxy allows for a single server to appear to be the endpoint for many servers behind it. A company moves a popular website to a new web host. Which of the following will change as a result? The IP address will certainly change.

source port

A source port is a high numbered port chosen from a special section of ports known as ephemeral ports. needed so that when the web server replies, the computer making the original request can send this data to the program that was actually requesting it

Network Address Translation (NAT)

A technique that allows private IP addresses to be used on the public Internet. NAT is a method of mapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device.

ethernet frame

A term referring to an Ethernet data link header and trailer, plus the data encapsulated between the header and trailer.

nslookup

A utility that is used to test and troubleshoot domain name servers.

What is the correct term for the list of IP addresses and the MAC addresses associated with them?

ARP table

What protocol is used to discover the hardware address of a node with a certain IP address?

ARP table, An ARP table is just a list of IP addresses and the MAC addresses associated with them.

The final step of the DHCP Discovery process is known as ______.

Acknowledgement. When the DHCP server receives the DHCPREQUEST message from the client, the configuration process enters its final phase. The acknowledgement phase involves sending a DHCPACK packet to the client.

ARP stands for

Address Protocol Resolution

There are ____ octets in an IP address.

An IP address is, as such, generally shown as 4 octets of numbers from 0-255 represented in decimal form instead of binary form. For example, the address 168.212.

A new Domain Name System (DNS) server is being configured. Which record type is used to declare a new zone?

An SOA record establishes a zone and maintains authority over the zone.

anycast

An anycast communication flow is a one-to-nearest (from the perspective of a router's routing table) flow.

Application layer

Application layer allows these applications to communicate in a way they understand.

Which form of Digital Subscriber Line (DSL) features differing upload and download speeds?

Asymmetric Digital Subscriber Line (ADSL) connections feature different speeds for outbound and incoming data.

What is used to determine when the communications channels are clear and when a device is free to transmit data?

CSMA/CD

Cellular network towers are configured in such a way so that they avoid what type of problem?

Cell towers are similar to wireless access points. Configuration of a tower includes avoiding overlap issues.

CIDR simplifies how routers and other network devices need to think about the parts of an IP address, but it also allows for more arbitrary network sizes. What does CIDR stand for?

Classless Inter-Domain Routing

The "www" portion of a domain is known by which of the given options? Check all that apply.

DHCP

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

DHCP

While in an interactive nslookup session, you'd use the ______ keyword to change the DNS server you're using.

DNS

What is the importance of using DNS?

DNS ensures the Internet is not only user-friendly but also works smoothly, loading the content users ask for quickly and efficiently.

Which are a type of interior gateway protocol? (Check all that apply)

Distance-vector protocols: A router using a distance vector protocol basically just takes its routing table, which is a list of every network known to it and how far away these networks are in terms of hops. Then the router sends this list to every neighboring router, which is basically every router directly connected to it. Link-state routing protocols: Link state protocols get their name because each router advertises the state of the links of each of its interfaces. This information about each router is propagated to every other router on an autonomous system.

DNS servers

Domain Name System server: a database of domain names and associated IP addresses stored on servers. There are many DNS servers distributed across the Internet, which communicate with each other.

DNS stands for ____________

Domain name system

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

DHCP

Dynamic Host Configuration Protocol

A Transmission Control Protocol (TCP) connection is in working order and both sides can send each other data. What is the TCP socket state?

ESTABLISHED

A single octet in an IP address represents what range of decimal numbers?

Eight bits of data, or a single octet, can represent all decimal numbers from 0-255.

A _______ record is responsible for resolving an IP to a domain name.

Explanation: A pointer (PTR) record is a type of Domain Name System (DNS) record that resolves an IP address to a domain or host name, unlike an A record which points a domain name to an IP address. PTR records are used for the reverse DNS lookup

Which Fiber implementation is often referred to as Fiber To The Premises (FTTP)? Check all that apply.

Fiber To The Building (FTTB)Fiber To The Home (FTTH)

Fiber optic cable from a service provider can be delivered directly to the end user. Which implementation delivers data to a cabinet for distribution?

Fiber To The Neighborhood (FTTN) defines fiber technology used to deliver data to a single physical cabinet that serves a population.

FTP

File transfer protocol, is an older method used for transferring files from one computer to another, but you still see it in use today.

For all IPv6 addresses, the network ID is always the first ______ bits.

For all IPv6 addresses, the first 64 bits are the network ID and the last 64 bits are the host ID.

an internal system behind a firewall needs to be configured for remote access. How should Network Address Translation be configured?

Forwarding external traffic to the system by using port forwarding maintains internal address secrecy.

The number system that has 16 numerals is known as _____.

Hexadecimal is the name of the numbering system that is base 16. This system, therefore, has numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15. That means that two-digit decimal numbers 10, 11, 12, 13, 14, and 15 must be represented by a single numeral to exist in this numbering system.

The IPv6 header field that indicates how many routers can forward a packet before it's discarded is called the ________.

Hop Limit Hop Limit The Hop Limit field indicates the maximum number of links over which the IPv6 packet can travel before being discarded. The size of this field is 8 bits.Jun 15, 2012

A DNS TTL determines what?

How long a DNS entry is allowed to be cached

Question 3 A hybrid cloud is ________________.

Hybrid cloud is a solution that combines a private cloud with one or more public cloud services, with proprietary software enabling communication between each distinct service. A hybrid cloud strategy provides businesses with greater flexibility by moving workloads between cloud solutions as needs and costs fluctuate.

The organization responsible for DNS at a global level is ________.

ICANN ICANN is the global non-profit organization responsible for coordinating the Internet's core systems of unique identifiers, most notably the Domain Name System (DNS).

Question 1 The protocol used to communicate network errors is known as

ICMP (Internet Control Message Protocol) is an error-reporting protocol that network devices such as routers use to generate error messages to the source IP address when network problems prevent delivery of IP packets.

Network configuration

IP address, subnet mask, gateway, DNS server

An IPv6 address is how many bits long?

IPv6 uses 128-bit (2128) addresses, allowing 3.4 x 1038 unique IP addresses. This is equal to 340 trillion trillion trillion IP addresses. IPv6 is written in hexadecimal notation, separated into 8 groups of 16 bits by the colons, thus (8 x 16 = 128) bits in total.Sep 24, 2019

Which technology is NOT a form of broadband?

ISDN; ISDN is an older analog dial-up method that is faster than traditional dial-up.

IPv6 Compression Rules

If you have consecutive fields of zeroes, they can be expressed with two colons. The key rule: you can only do this zero compression once in an IPv6 address. Example: Original format: 1234:1234:0000:0000:0000:0000:3456:3434 Using zero compression: 1234:1234::3456:3434 Leading zeroes in any 16-bit field can be dropped, but each block you do this with must have at least one number remaining. If the block is all zeroes, you have to leave one zero. This is leading zero compression. Example: Original format: 1234:0000:1234:0000:1234:0000:0123:1234 With leading zero compression: 1234:0:1234:0:1234:0:123:1234 Recap.. Zero compression: Allowed only once per address. Leading zero compression: Perform as often as you like in an address.

ICMP stands for ________.

Internet Control Message Protocol

If a TCP socket is ready and listening for incoming connections, it's in the ______ state.

LISTEN

Unlike Linux and Mac systems, on a Windows system, the ping command sends how many echo requests?

Linux and Mac systems send echo requests until the ping command is stopped. A Windows system sends only 4 echo requests by default.

We're running out of IP addresses. We'll need to have a way to use non-routable address space!

NAT

As an IT decision maker, you plan to satisfy business needs by using software as a service. Which option do you deploy?

Office 365

Traceroute uses UDP packets on which of the following operating systems? Check all that apply.

On Linux and macOS, traceroute sends UDP packets to very high port numbers.

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?

On Windows, Test-NetConnection is a command with some of the similar functionality. If you run Test-NetConnection with only a host specified, it will default to using an ICMP echo request, much like the program ping.

Which two tools function similar to traceroute? Check all that apply. nslookup pathping mtr netcat

On Windows, the command has a shortened name tracert, and defaults to using ICMP echo request. On all platforms, traceroute has more options than can be specified using command line flags. Two more tools that are similar to traceroute are mtr on Linux and MacOS and pathping on Windows.

If the transmitting device would like for the receiving device to push currently buffered data to the application on the receiving end immediately, it would set the ____ flag.

PSH

you are sending a very small amount of information that you need the listening program to respond to immediately. Which Transmission Control Protocol (TCP) flag will be used?

PSH

What size is an Internet Protocol (IP) v6 payload field?

Payload Length The Payload Length field indicates the length of the IPv6 payload. The size of this field is 16 bits. The Payload Length field includes the extension headers and the upper-layer PDU. With 16 bits, an IPv6 payload of up to 65,535 bytes can be indicated.

What two benefits are a result of configuring a wireless mesh network? Check all that apply.

Performance increases when access points are configured in a mesh where all points are connected to each other. Range increases when access points are configured in a mesh where all points are connected to each other.

Another term for POTS, or the Plain Old Telephone System, is _______________.

Phone Switched Transport Network.

On a Local Area Network, or LAN, what identification do nodes use to communicate with each other internally?

Physical MAC addresses

PaaS stands for ________. A) platform as a service B) public as accessible service C) protocol as a service D) private accessibility add-on service

Platform as a service (PaaS) is a cloud computing model where a third-party provider delivers hardware and software tools to users over the internet.

UDP (User Datagram Protocol)

Protocol that operates instead of TCP in applications where delivery speed is important and quality can be sacrificed.

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.

RFC stands for

Realtime frame check

An IT engineer is planning a website upgrade with load balancing features. What technology is used?

Reverse Proxy. A website can be defined as a collective name used to describe series of web pages that are linked together with the same domain name. A web server is a type of computer that run websites and distribute web pages as they are being requested over the internet by end users (clients). Basically, when an end user (client) request for a website by adding or typing the uniform resource locator (URL) on the address bar of a web browser; a request is sent to the internet to view the corresponding web pages (website) associated with that particular address (domain name). In Computer Networking, a single server can be configured to appear as an endpoint for multiple servers acting behind it through the use of a reverse proxy. Hence, a reverse proxy is a type of server that is placed right in front of other servers such as a web server and it is typically configured to forward or route an end user's requests to those multiple servers sitting behind it. Furthermore, when a reverse proxy is properly configured, it helps to ensure security, reliability and optimum performance of a network through load balancing. Therefore, server load balancing is a process that allows the even distribution of network traffic across multiple servers and it involves the use of a technology referred to as a reverse proxy.

Which Transmission Control Protocol (TCP) flag is used to make sure the receiving end knows how to examine the sequence number field?

SYN

TCP flags

SYN; ACK; URG; RST; PSH; FIN CWR; ECE Port Scanning Fin; NULL; XMAS

Demultiplexing

Same complex as multiplexing, just at the receiving end, it's taking traffic that's all aimed at the same node and delivering it to the proper receiving service.

A communication between two devices is over the maximum limit of an ethernet frame size. The Transmission Control Protocol (TCP) splits up the data into segments. Which field in the header helps keep track of the many segments?

Sequence number

A communication sent through Transmission Control Protocol (TCP) arrives out of order. What allows the data to be put back together in the correct order?

Sequence numbersSequence numbers allow the data to be put back together in the correct order.

QoS services are protocols that allow routers to make decisions about which IP datagram may be more important than others. Which IP header field would QoS details be found?

Service type field, Nice job! These 8 bits can be used to specify details about quality of service, or QoS, technologies. The important take away about QoS is that they're services that allow routers to make decisions about which IP datagram may be more important than others.

Question 2 Office 365 Outlook is an example of _______.

Software as a service (SaaS) allows users to connect to and use cloud-based apps over the Internet. Common examples are email, calendaring, and office tools (such as Microsoft Office 365). SaaS provides a complete software solution that you purchase on a pay-as-you-go basis from a cloud service provider.

What is the process of taking a large network and splitting it up into many individual and smaller subnetworks called?

Subnetting

A wireless network does not benefit like a wired network does, when it comes to collision reduction. Which device reduces collisions on a wired network?

Switches remember which computers are on which physical interfaces, so traffic is only sent to the intended node.

the most common example of a connection-oriented protocol is _____

TCP

Which two protocols work at the transport layer and ensures that data gets to the right applications running on those nodes?

TCP and UDP

TCP segment is made up of a

TCP header and a data section header - split into many fields containing a lot of info. - source port and destination port data section - another payload are for where the application layer places its data Sequence number - a 32-bit number that's used to keep track of where in a sequence of TCP segments this one is expected to be. You might remember that lower on our protocol stack, there are limits to the total size of what we send across the wire. In Ethernet frame, it's usually limited in size to 1,518 bytes, but we usually need to send way more data than that. At the transport layer, TCP splits all of this data up into many segments. The sequence number in a header is used to keep track of which segment out of many this particular segment might be. The acknowledgment number is the number of the next expected segment. In very simple language, a sequence number of one and an acknowledgement number of two could be read as this is segment one, expect segment two next. The data offset field comes next. This field is a four-bit number that communicates how long the TCP header for this segment is. This is so that the receiving network device understands where the actual data payload begins we have six bits that are reserved for the six TCP control flags The next field is a 16-bit number known as the TCP window. A TCP window specifies the range of sequence numbers that might be sent before an acknowledgement is required The next field is a 16-bit checksum. It operates just like the checksum fields at the IP and Ethernet level. Once all of this segment has been ingested by a recipient, the checksum is calculated across the entire segment and is compared with the checksum in the header to make sure that there was no data lost or corrupted along the way. The Urgent pointer field is used in conjunction with one of the TCP control flags to point out particular segments that might be more important than others. This is a feature of TCP that hasn't really ever seen adoption and you'll probably never find it in modern networking. Even so, it's important to know what all sections of the TCP header are. Next up, we have the options field. Like the urgent pointer field, this is rarely used in the real world, but it's sometimes used for more complicated flow control protocols. Finally, we have some padding which is just a sequence of zeros to ensure that the data payload section begins at the expected location.

IP datagram encapsulates a

TCP segment

Which layer in the Transmission Control Protocol/Internet Protocol (TCP/IP) model is responsible for delivering data between two nodes?

TCP/IP relies on the transport layer to effectively control communications between two hosts. When an IP communication session must begin or end, the transport layer is used to build this connection.

On Windows, one of the tools you can use to verify connectivity to a specific port is ________.

Test-NetConnection

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?

The "-v" flag, which stands for verbose, is useful as it formats the command's output to be readable to human eyes.

An A Record contains what?

The "A" stands for "address" and this is the most fundamental type of DNS record: it indicates the IP address of a given domain. For example, if you pull the DNS records of cloudflare.com, the A record currently returns an IP address of: 104.17. 210.9. A records only hold IPv4 addresses.

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

The IP address will certainly change.

DNS (Domain Name System)

The Internet's system for converting alphabetic names into numeric IP addresses.

The ping utility sends what message type?

The Ping utility uses the echo request, and echo reply messages within the Internet Control Message Protocol (ICMP), an integral part of any IP network. When a ping command is issued, an echo request packet is sent to the address specified.

What immediately follows the Start Frame Delimiter in an ethernet frame?

The SFD is designed to break the bit pattern of the preamble and signal the start of the actual frame. The SFD is immediately followed by the destination MAC address, which is the first field in an Ethernet frame.

The Ethernet protocol functions at which layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?

The data-link layer identifies the network protocol type of the packet, in this case TCP/IP. It also provides error control and "framing." Examples of data-link layer protocols are Ethernet IEEE 802.2 framing and Point-to-Point Protocol (PPP) framing.

Which Internet Protocol (IP) v6 field is identical in purpose to the TTL field in an IPv4 header?

The hop limit field is an 8-bit field that's identical in purpose to the Time To Live (TTL) field in an IPv4 header.

Which octet of the subnet mask 255.255.255.0 will tell the router the corresponding host ID?

The last octet The size of a subnet is entirely defined by its subnet mask. So for example, with a subnet mask of 255.255.255.0, we know that only the last octet is available for host IDs, regardless of what the size the network and subnet IDs are.

Network Address Translation (NAT) technology provides a major benefit for which of these network problems?

The main advantage of NAT (Network Address Translation) is that it can prevent the depletion of IPv4 addresses. NAT (Network Address Translation) can provide an additional layer of security by making the oringinal source and destination addresses hidden.

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?

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

collision domain

The portion of an Ethernet network in which collisions could occur if two nodes transmit data at the same time.

When a client computer sends a request to a Domain Name System (DNS) server, what type of packet is sent?

The requesting client initiates a query with a DNS server by sending a Synchronize (SYN) packet as a first step in the three-way handshake.

What does demultiplexing and multiplexing make possible?

The same computer might host an internal website, the mail server for the company, file server for sharing files, a print server for sharing network printers, pretty much anything. This is all possible because of multiplexing and demultiplexing, and the addition of ports to our addressing scheme.

What information will you find in the 16-bit field in an IP datagram

The total length of the datagram its attached to. The final field is a 16-bit field known as the total length field. It is used to indicate the total length of the IP datagram it's attached to.

Caching and recursive name servers are generally provided by an ISP or your local network.

Their purpose is to store domain name lookups for a certain amount of time.

How many address fields does an 802.11 header have?

There are four address fields in the MAC frame format. These fields are used to indicate the basic service set identifier (BSSID), source address (SA), destination address (DA), transmitting STA address (TA), and receiving STA address (RA). Certain frames may not contain some of the address fields.

Which configuration is considered to be a common way to increase security in a wireless network?

There are three principal ways to secure a wireless network. For closed networks (like home users and organizations) the most common way is to configure access restrictions in the access points. Those restrictions may include encryption and checks on MAC address.

Why is TCP a protocol that's super reliant on acknowledgements?

This is done in order to make sure that all expected data is actually being received and that the sending device doesn't waste time sending data that isn't being received.

TTL stands for

Time to Live

What is the purpose of an ARP response?

To let a computer broadcasting an ARP message know what MAC address to put into the destination hardware address field. The node that wants to send data sends a broadcast ARP message to the MAC broadcast address which is all F's. When the network interface receives this ARP broadcast, it sends back what's known as an ARP response. This response message will contain the MAC address for the network interface in question.

During a traceroute, which action does a router perform to the value in the Time To Live (TTL) field?

Traceroute sends packets with TTL values that gradually increase from packet to packet, starting with TTL value of one. Routers decrement TTL values of packets by one when routing and discard packets whose TTL value has reached zero, returning the ICMP error message ICMP Time Exceeded.

T1 is short for

Transmission System 1

Transport layer

Transport layer allows traffic to be directed to specific network applications. - multiplexing and demultiplexing traffic - establishing long running connections - ensuring data integrity through error checking and data verification.

What transport layer protocol does DNS normally use?

UDP

The control flag that isn't really in use by modern networks is the _____ flag.

URG flag

What Internet system, that still exists today, was built during the early days of dial-up networking?

USENET

Our traveling sales people need to access internal resources on the road!

VPN

The very first field in an IPv6 header is the _______.

Version field

WPA2 uses a key that's ____ bits long.

WPA uses either a 64-bit or 128-bit key, the most common being 64-bit for home routers. WPA2-PSK and WPA2-Personal are interchangeable terms. So if you need to remember something from all this, it's this: WPA2 is the most secure protocol and AES with CCMP is the most secure encryption.

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

What port on a name server is used for User Datagram Protocol (UDP) name request packets? DNS uses port 53 over UDP for name resolution communications. A new Domain Name System (DNS) server is being configured.

What does the subnet mask 255.255.255.0 tell a router?

Which part of an IP address is the subnet ID and which is the host ID. The purpose of the part of the mask that reads 255, or all 1s in binary, is to tell a router what part of an IP address is the subnet ID.

WPA stands for _______.

WiFi Protected Access

The original and flawed wireless security protocol is known as _____.

Wired Equivalent Privacy (WEP): The original encryption protocol developed for wireless networks. As its name implies, WEP was designed to provide the same level of security as wired networks. However, WEP has many well-known security flaws, is difficult to configure, and is easily broken.

Television broadcasts were originally delivered by using which technology?

Wireless; Television has historically moved in the opposite direction of networking as broadcasts were sent and received with antennas.

A device involved in a Transmission Control Protocol (TCP) connection is ready to close the connection. The other device in the connection agrees. What has occured?

a four way handshake occurs when a connection is closed

VPN (Virtual Private Network)

a network that uses a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization's network.

Firewall

a part of a computer system or network that is designed to block unauthorized access while permitting outward communication.

To reduce internal collision domains

a switch is the solution

DNS

a system that converts domain names into IP addresses

Traceroute

a utility application that monitors the network path of packet data sent to a remote computer

ACK

a value of one in this field means that the acknowledgement number field

Connection-oriented protocols protect against dropped data by forming connections and using what type of constant stream?

acknowledgements

Which field in a Transmission Control Protocol (TCP) header provides the next expected segment?

acknowledgment number

Select all that are true. One domain name can point to one IP. One domain name can point to many IPs. Many domain names can point to the same IP.

all are true

What is the fifth layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?

application

Interior gateway protocols are used by routers in order to share information within a single

autonomous system

A baud rate is a measurement of the number of ______________________.

bits that can be sent across a telephone line every second.

what connection type is known as "always on"?

broadband

The transmission method that sends data to every device on a LAN is known as a _____ transmission.

broadcast

Something that requests data from a server is known as a ____.

client

A connection has been terminated and no communication is possible. What is the Transmission Control Protocol (TCP) socket state?

closed

What is the name of the provision of services based around hardware virtualization?

cloud computing In hardware virtualization, software called hypervisor is used. With the help of hypervisor virtual machine, software embedded into the hardware component of the server. The work of hypervisor is that it manages the physical hardware resource which is shared between the customer and the provider.

A network segment where only one device can communicate at a time is known as a _____.

collision domain

TCP establishes

connections used to send long chains of sengments of data

CMTS (Cable Modem Termination System)

connects lots of different cable connections to an ISP's core network.

What type of cable communicates binary data by changing the voltage between two ranges?

copper

Which layer abstracts away the need for any other layers to care about what hardware is in use?

data link

Application layer data lives in the _____ section of the transport layer protocol.

data payload

For Internet Protocol (IP) v6 traffic to travel on an IP v4 network, which two technologies are used? Check all that apply.

datagrams

What is the term for the place one network ends and another begins?

demarcation point

The concept of taking traffic that's all aimed at the same node and delivering it to the proper receiving service is known as _________.

demultiplexing

Destination port

destination port is the port of the service the traffic is intended for

An organization responsible for assigning individual domain names to other organizations or individuals is known as a(n) ______.

dns registrar

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?

domain transfer

When you send an echo request message with the ping program, a successful attempt will return a(n) ______ message.

echo reply

The entirety of a packet at one layer becoming the payload section at another layer is known as

encapsulation

Ports that are generally used to establish outbound connections are known as ______ ports.

ephemeral

The ability for a protocol or program to determine that something went wrong is known as ________.

error detection

The most common data link layer protocol for wired connections is _____.

ethernet

The first field in an 802.11 header is known as a ________.

frame control field

An 802.11 frame contains a number of fields. Which field describes the version of 802.11 that is being used?

frame control; The frame control field contains a number of subfields to describe the frame and processing. This includes the version of 802.11 being used.

A section of the radio spectrum that's been agreed upon to be used for certain communications is known as a _______.

frequency band A frequency band is a certain section of the radio spectrum that's been agreed upon to be used for certain communications. ... This specific frequency band is called the FM broadcast band.

With virtualization, a single physical machine, called a host, can run many individual virtual instances, called ______.

guests With virtualization, a single physical machine called a host could run many individual virtual instances called guests. An operating system expects to be able to communicate with the underlying hardware in certain ways. Hardware virtualization platforms employ what's called a hypervisor.

A Local Area Network (LAN) uses Category 6 cabling. An issue with a connection results in a network link degradation and only one device can communicate at a time. What is the connection operating at?

half duplex

The equivalent of the TTL field in an IPv4 header is known as the ______ field in an IPv6 header.

hop limit

You have installed a device at the physical layer. All of the systems you connect to this device will talk to each other at the same time. What have you installed?

hub

A company runs sensitive technologies locally, while entrusting less-sensitive technologies to a broader user base. Which cloud delivery model is being used?

hybrid; A combination of cloud delivery models make up a hybrid type of deployment. In this case, both private and public models are being used.

Multiplexing

in the transport layer means that nodes on the network have the ability to direct traffic toward many different receiving services.

biggest difference between TCP and UDP

is that UDP is connectionless.

An Internet connection problem for customers is found to be outside a carrier's regional office. As a result, which area needs troubleshooting?

local loop

TTL is used to

make sure than an undeliverable packet doesn't spend all of eternity waiting for delivery

What term defines keeping the address of one computer secret from another?

masquerading

another name for cellular networking is ______ networking.

mobile

What process sends ones and zeroes across network cables?

modulation

A network has the ability to direct traffic toward all of the receiving services. What provides this ability in the transport layer?

multipilexing

A DNS resolver tool available on all major desktop operating systems is __________.

nslookup. One of the oldest tools for DNS lookup is nslookup . This tool is available on all major operating systems and is quite well known.Feb 12, 2015

USENET

one of the earliest discussion forums in use today, in which participants discuss topics in categories called newsgroups

Which technology is used as a demarcation point for fiber optics?

optical network terminator

Which section in an ethernet frame contains the data from higher layers, such as Internet Protocol (IP) and the transport and application layers?

payload

Which solution eliminates the need for dedicated high-speed WAN connections between sites?

point-to-point vpn

FTP traditionally listens on...

port 21 so if you wanted to establish a connection to an FTP server running on the same IP that our example web server was running on, you direct traffic to 10.1.1.100 port 21.

If we want tor request the webpage from a web server running on a computer listening on IP 10.1.1.100, the traffic would be directed to port...

port 80

port for HTTP or unencrypted web traffic

port 80

A wireless channel is ____________.

portion of a frequency band

The transport layer handles multiplexing and demultiplexing through what type of device?

ports

The transport layer handles multiplexing and demultiplexing through...

ports

The first part of an Ethernet frame is known as the _____.

preamble

A defined set of standards that computers must follow in order to communicate properly is known as a _____.

protocol

TCP (Transmission Control Protocol)

provides reliable, ordered, and error-checked delivery of a stream of packets on the internet. TCP is tightly linked with IP and usually seen as TCP/IP in writing.

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

round robin.

A 32-bit number that's used to keep track of where you are in a sequence of TCP segments is known as a(n) ______ number.

sequence

A communication sent through Transmission Control Protocol (TCP) arrives out of order. What allows the data to be put back together in the correct order?

sequence numbers

A user logs on to a laptop and opens her email. What device will provide emails to the laptop?

server

Cable Internet access can be described with which feature?

shared bandwidth

A point-to-point VPN is also known as a _

site-to-site VPN; A point-to-point VPN can also be referred to as a site-to-site VPN.

Which field in a Transmission Control Protocol (TCP) header is chosen from ephemeral ports

source port

Which field in a Transmission Control Protocol (TCP) header is chosen from ephemeral ports?

source port

The "www" portion of a domain is known by which of the given options? Check all that apply.

subdomain host

The process of taking a large network and splitting it up into many individual and smaller subnetworks is known as

subnetting, Subnetting allows for much finer-grained controls of network sizes than the old class system could support.

What is the process of taking a large network and splitting it up into many individual and smaller subnetworks called?

subnetting, Subnetting is the process of taking a large network and splitting it up into many individual and smaller subnetworks, or subnets.

The transport layer handles multiplexing and demultiplexing through what type of device?

switches

Ports 1-1023 are known as ______ ports.

system

What does a value of one in an ACK control flag represent?

the acknowledgement number field should be examined

The checksum doesn't compute for a packet sent at the Internet Protocol (IP) level. What will happen to the data?

the data will be discarded

You need to identify the manufacturer of a network interface. Where will you look for this information?

the first 3 octets of a MAC address The first three octets of a MAC address are known as the Organizationally Unique Identifier (OUI). These are assigned to individual hardware manufacturers.

Where is the Start Frame Delimiter (SFD) found in an ethernet frame?

the last byte of the preamble

The sequence of SYN, SYN/ACK, and ACK packets is known as the _________.

three-way handshake

How does TCP establish a connection?

through the use of TCP flags

What information will you find in the 16-bit field in an IP datagram?

total length of the datagram its attached to

What type of transmission will have a zero in a special bit in the destination Media Access Control (MAC) address?

unicast

Which field in a Transmission Control Protocol (TCP) header is not typically used in modern networking?

urgent pointer

URG

value of one here indicates that the segment is considered urgent and that the urgent pointer field has more data about this

When NAT hides the source IP of an originating device, this is known as ________.

when Nat hides the source of IP of an organisation device this is known as IP masquerading

When is using the Transmission Control Protocol (TCP) most appropriate?

when you make a phone call

Question 1 WAN stands for

wide area network