TCP/IP Flashcards by Gielyn Gener

The __________ suite was designed and implemented by the Department of Defense (DoD) to ensure and preserve data integrity as well as maintain communications in the event of catastrophic war.

Transmission Control Protocol/Internet Protocol (TCP/IP)

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What is DoD?

Department of Defense

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True or False:
TCP/IP network can be a secure, dependable and resilient one.

True

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TCP first came on the scene way back in 1973, and in 1978, it was divided into two distinct protocols: ____and ____.

TCP and IP

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Later, in 1983, TCP/IP replaced the ______ and was authorized as the official means of data transport for anything connecting to ARPAnet, the Internet’s ancestor.

Network Control Protocol (NCP)

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The DoD’s_____ created this ancient network way back in 1957 in a cold war reaction to the Soviet’s launching of Sputnik.

Advanced Research Projects Agency (ARPA)

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In 1983, ARPA was redubbed DARPA and divided into _____ and _____ until both were finally dissolved in 1990.

ARPAnet and MILNET

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It may be counterintuitive, but most of the development work on TCP/IP happened at UC Berkeley in Northern California, where a group of scientists were simultaneously working on the Berkeley version of UNIX, which soon became known as the _____ series of UNIX versions.

Berkeley Software Distribution (BSD)

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______ bundled with TCP/ IP began as shareware in the world of academia. As a result, it became the foundation for the tremendous success and unprecedented growth of today’s Internet as well as smaller, private and corporate intranets.

BSD Unix

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________ —that sealed its popularity because this quality guarantees a solid connection between myriad hardware and software platforms with no strings attached.

TCP/IP family of protocols

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The DoD model is basically a condensed version of the OSI model that comprises four instead of seven layers:

Process/Application layer
Host-to-Host layer or Transport layer
Internet layer
Network Access layer or Link layer

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______ defines protocols for node-to-node application communication and controls user-interface specifications.

Process/Application layer

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_______ parallels the functions of the OSI’s Transport layer, defining protocols for setting up the level of transmission service for applications.

The Host-to-Host layer or Transport layer

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It tackles issues like creating reliable end-to-end communication and ensuring the error-free delivery of data. It handles packet sequencing and maintains data integrity.

The Host-to-Host layer or Transport layer

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The _______ corresponds to the OSI’s Network layer, designating the protocols relating to the logical transmission of packets over the entire network.

Internet layer

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It takes care of the addressing of hosts by giving them an IP (Internet Protocol) address and handles the routing of packets among multiple networks.

Internet layer

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The _______ or Link layer implements the data exchange between the host and the network.

Network Access layer

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It was one of the first Internet standards, developed in 1969, and is the chameleon of protocols—its specialty is terminal emulation.

Telnet

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It allows a user on a remote client machine, called the ______ client, to access the resources of another machine, the Telnet server, in order to access a command-line interface.

Telnet

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_____ achieves this by pulling a fast one on the Telnet server and making the client machine appear as though it were a terminal directly attached to the local network. This projection is actually a software image—a virtual terminal that can interact with the chosen remote host.

Telnet

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A drawback is that there are no encryption techniques available within the _____ protocol, so everything must be sent in clear text, including passwords!

Telnet

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_______ sets up a secure session that’s similar to Telnet over a standard TCP/IP connection and is employed for doing things like logging into systems, running programs on remote systems, and moving files from one system to another. And it does all of this while maintaining an encrypted connection.

Secure Shell (SSH) protocol

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______ actually lets us transfer files, and it can accomplish this between any two machines using it.

File Transfer Protocol (FTP)

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_____ isn’t just a protocol; it’s also a program. Operating as a protocol, it is used by applications. As a program, it’s employed by users to perform file tasks by hand.

File Transfer Protocol (FTP)

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_____ also allows for access to both directories and files and can accomplish certain types of directory operations, such as relocating into different ones

File Transfer Protocol (FTP)

______ is the stripped-down, stock version of FTP, but it’s the protocol of choice if you know exactly what you want and where to find it because it’s fast and so easy to use!

Trivial File Transfer Protocol (TFTP)

It doesn’t offer the abundance of functions that FTP does because it has no directory-browsing abilities, meaning that it can only send and receive files

Trivial File Transfer Protocol (TFTP)

______ collects and manipulates valuable network information

Simple Network Management Protocol (SNMP)

It gathers data by polling the devices on the network from a network management station (NMS) at fixed or random intervals, requiring them to disclose certain information, or even asking for certain information from the device.

Simple Network Management Protocol (SNMP)

Network devices can inform the _____ station about problems as they occur so the network administrator is alerted.

NMS; Simple Network Management Protocol (SNMP)

______ receives something called a baseline—a report delimiting the operational traits of a healthy network.

Simple Network Management Protocol (SNMP)

This protocol can also stand as a watchdog over the network, quickly notifying managers of any sudden turn of events. These network watchdogs are called _______, and when aberrations occur, agents send an alert called a ______ to the management station.

agents; trap

It’s used to manage communications between web browsers and web servers and opens the right resource when you click a link, wherever that resource may actually reside.

Hypertext Transfer Protocol (HTTP)

______ is also known as Secure Hypertext Transfer Protocol.

Hypertext Transfer Protocol Secure (HTTPS)

It uses _____. It referred to as ______ or S-HTTP, which were slightly different protocols, but since Microsoft supported HTTPS, it became the de facto standard for securing web communication.

Secure Sockets Layer (SSL); SHTTP under Hypertext Transfer Protocol Secure (HTTPS)

It’s a secure version of HTTP that arms you with a whole bunch of security tools for keeping transactions between a web browser and a server secure.

Hypertext Transfer Protocol Secure (HTTPS)

Professor David Mills of the University of Delaware for coming up with this handy protocol that’s used to synchronize the clocks on our computers to one standard time source (typically, an atomic clock).

Network Time Protocol (NTP)

It works by synchronizing devices to ensure that all computers on a given network agree on the time

Network Time Protocol (NTP)

It resolves hostnames—specifically, Internet names.

Domain Name Service (DNS)

It allows to use a domain name to specify an IP address. You can change the IP address as often as you want and no one will know the difference.

Domain Name Service (DNS)

_______ assigns IP addresses to hosts. It allows for easier administration and works well in small to very large network environments.

Dynamic Host Configuration Protocol (DHCP)

______ assigns an IP address to a host but the host’s hardware address must be entered manually in a BootP table.

BootP

It is also used to send an operating system that a host can boot from.

BootP

DHCP server can provide:

- IP address - Subnet mask - Domain name - Default gateway (routers) - DNS server address - WINS server address

Dynamic Host Configuration Protocol (DHCP) is connectionless, which means it uses _______ at the Transport layer, also known as the Host-to-Host layer

User Datagram Protocol (UDP)

This is the four-step process a client takes to receive an IP address from a DHCP server:

1. The DHCP client broadcasts a DHCP Discover message looking for a DHCP server (Port 67). 2. The DHCP server that received the DHCP Discover message sends a layer 2 unicast DHCP Offer message back to the host. 3. The client then broadcasts to the server a DHCP Request message asking for the offered IP address and possibly other information. 4. The server finalizes the exchange with a unicast DHCP Acknowledgment message.

A _____ address conflict occurs when two hosts use the same IP address.

DHCP

______ checks for conflicts using the Ping program to test the availability of the address before it’s assigned from the pool. If no host replies, then the it assumes that the IP address is not already allocated.

DHCP server

A host uses something called a ______ to help avoid a possible duplicate address.

gratuitous ARP

True or False: The DHCP client sends an ARP broadcast out on the local LAN or VLAN using its newly assigned address to solve conflicts before they occur.

True

Windows operating systems provide a feature called _______.

Automatic Private IP Addressing (APIPA)

True or False: With APIPA, clients can automatically self-configure an IP address and subnet mask—basic IP information that hosts use to communicate—when a DHCP server isn’t available.

True

The IP address range for APIPA is ______ through 169.254.255.254. The client also configures itself with a default Class B subnet mask of 255.255.0.0.

169.254.0.1

The main purpose of the ________ is to shield the upper-layer applications from the complexities of the network.

Host-to-Host layer; The Host-to-Host or Transport Layer Protocols

Two Protocols At the The Host-to-Host or Transport Layer Protocols:

1. Transmission Control Protocol (TCP) 2. User Datagram Protocol (UDP)

______ takes large blocks of information from an application and breaks them into segments.

Transmission Control Protocol (TCP)

It numbers and sequences each segment so that the destination’s TCP stack can put the segments back into the order the application intended.

Transmission Control Protocol (TCP)

True or False: After these segments are sent on the transmitting host, TCP waits for an acknowledgment of the receiving end’s TCP virtual circuit session, retransmitting any segments that aren’t acknowledged.

True

________ is basically the scaled-down economy model of TCP, which is why UDP is sometimes referred to as a thin protocol. Like a thin person on a park bench, a thin protocol doesn’t take up a lot of room—or in this case, require much bandwidth on a network.

User Datagram Protocol (UDP)

_______ doesn’t offer all the bells and whistles of TCP either, but it does do a fabulous job of transporting information that doesn’t require reliable delivery, using far less network resources.

User Datagram Protocol (UDP)

TCP and UDP must use ______ to communicate with the upper layers because these are what keep track of different conversations crossing the network simultaneously.

port numbers

True or False: Internet layer has functions relating to routing

True

True or False: The Internet layer’s second duty is to provide a single network interface to the upper-layer protocols.

True

______ essentially is the Internet layer. The other protocols found here merely exist to support it.

Internet Protocol (IP)

holds the big picture and could be said to “see all,” because it’s aware of all the interconnected networks. It can do this because all the machines on the network have a software, or logical, address called an ________

Internet Protocol (IP); IP address

______ works at the Network layer and is used by IP for many different services.

Internet Control Message Protocol (ICMP)

It is basically a management protocol and messaging service provider for IP. Its messages are carried as IP datagrams.

Internet Control Message Protocol (ICMP)

_____ is an annex to ICMP, which gives hosts extended capability in discovering routes to gateways.

RFC 1256

ICMP packets have the following characteristics:

They can provide hosts with information about network problems. They are encapsulated within IP datagrams.

______ finds the hardware address of a host from a known IP address.

Address Resolution Protocol (ARP)

An ______ is a numeric identifier assigned to each machine on an IP network.

IP address

It designates the specific location of a device on the network.

IP address

An _______ is a software address, not a hardware address—the latter is hard-coded on a network interface card (NIC) and used for finding hosts on a local network.

IP address

______ was designed to allow hosts on one network to communicate with a host on a different network regardless of the type of LANs the hosts are participating in.

IP addressing

A _____ is one digit, either a 1 or a 0.

Bit

A ____ is 7 or 8 bits, depending on whether parity is used.

byte

An _______, made up of 8 bits, is just an ordinary 8-bit binary number.

octet

This is the designation used in routing to send packets to a remote network—for example, 10.0.0.0, 172.16.0.0, and 192.168.10.0.

Network address

The address used by applications and hosts to send information to all nodes on a network is called the ______.

Broadcast address

An IP address consists of _______ of information. These bits are divided into four sections, referred to as octets or bytes, with each containing 1 byte (8 bits).

32 bits

You can depict an IP address using one of three methods:

Dotted-decimal, as in 172.16.30.56 Binary, as in 10101100.00010000.00011110.00111000 Hexadecimal, as in AC.10.1E.38

The _______ (which can also be called the network number) uniquely identifies each network. Every machine on the same network shares that network address as part of its IP address. For example, in the IP address 172.16.30.56, 172.16 is the network address.

network address

The node address is assigned to, and uniquely identifies, each machine on a network. This part of the address must be unique because it identifies a particular machine—an individual— as opposed to a network, which is a group. This number can also be referred to as a ______. In the sample IP address 172.16.30.56, the 30.56 specifies the node address.

host address

For the small number of networks possessing a very large number of nodes, they created the rank ______ network.

Class A

At the other extreme is the _____ network, which is reserved for the numerous networks with a small number of nodes.

Class C

The class distinction for networks between very large and very small is predictably called the _____ network. Subdividing an IP address into a network and node address is determined by the class designation of one’s network.

Class B

The designers of the IP address scheme decided that the first bit of the first byte in this network address must always be off, or 0. This means a ______ address must be between 0 and 127 in the first byte, inclusive.

Class A

True or False: Class A network is defined in the first octet between 0 and 127, and it can’t be less or more. Understand that 0 and 127 are not valid in a Class A network because they’re reserved addresses

True

True or False: In a Class B network, the RFCs state that the first bit of the first byte must always be turned on but the second bit must always be turned off. If you turn the other 6 bits all off and then all on, you will find the range for a Class B network: 10000000 = 128 10111111 = 191

True

True or False: Class B network is defined when the first byte is configured from 128 to 191.

True

True or False: For Class C networks, the RFCs define the first 2 bits of the first octet as always turned on, but the third bit can never be on. Following the same process as the previous classes, convert from binary to decimal to find the range. Here’s the range for a Class C network: 11000000 = 192 11011111 = 223

True

An IP address that starts at 192 and goes to 223, it is a Class __ IP address.

Class C

______ (224–239) is used for multicast addresses and _____ (240–255) for scientific purposes, but I’m not going into these types of addresses because they are beyond the scope of knowledge you need to gain from this book.

Class D ; Class E

These addresses can be used on a private network, but they’re not routable through the Internet. This is designed for the purpose of creating a measure of well-needed security, but it also conveniently saves valuable IP address space.

Private IP Addresses (RFC 1918)

True or False: Private IP addresses, ISPs, corporations, and home users only need a relatively tiny group of bona fide IP addresses to connect their networks to the Internet. This is economical because they can use private IP addresses on their inside networks and get along just fine.

True

_____, which basically takes a private IP address and converts it for use on the Internet.

Network Address Translation (NAT)

Used to test the IP stack on the local computer. Can be any address from 127.0.0.1 through 127.255.255.254

Loopback (localhost)

These are sent to all nodes on a LAN.

Layer 2 broadcasts

These are sent to all nodes on the network.

Broadcasts (layer 3)

This is an address for a single interface, and these are used to send packets to a single destination host.

Unicast

These are packets sent from a single source and transmitted to many devices on different networks. Referred to as “one-to-many.”

Multicast

layer 2 broadcasts are also known as _______—they only go out on a LAN, but they don’t go past the LAN boundary (router).

hardware broadcasts

True or False: There are the plain old broadcast addresses at layer 3. Broadcast messages are meant to reach all hosts on a broadcast domain. These are the network broadcasts that have all host bits on.

True

A ______ is defined as a single IP address that’s assigned to a network interface card and is the destination IP address in a packet—in other words, it’s used for directing packets to a specific host.

unicast

True or False: Multicast does allow point-to-multipoint communication, which is similar to broadcasts, but it happens in a different manner.

True

True or False: Multicast is that it enables multiple recipients to receive messages without flooding the messages to all hosts on a broadcast domain. However, this is not the default behavior—it’s what we can do with multicasting if it’s configured correctly!

True