Udemy Certification Review Exam Questions And Answers Well Defined.

DHCP - correct answers DHCP discover DHCP Offer DHCP Request DHC Pack Which command will you use to verify the status of an interface on a Cisco router? - correct answers show ip interface brief DNS - Domain Name System - correct answers A special service that translates domain names into IP addresses. ping - correct answers Use the ping command to check basic connectivity between two devices tracert - correct answers shows you all hops (routers) to the destination (the traceroute command on a Cisco device): Duplex - correct answers Full duplex means I can send and receive data at the same time. Half duplex means I can send or receive data. CDP (Cisco Discovery Protocol) - correct answers Thanks to this protocol you can view all directly connected devices. It works at Layer 2 of the OSI Model and does not need an IP address to recognize a device. Can be used by IP Phones as well. OSI MODEL - correct answers Pew Dead Ninja Turtles Smell pretty awful Physical Data link network transport session presentation application The Application Layer (L7) - correct answers An interface and set of protocols used for communication. NOTE: applications like Firefox, Outlook or IE do not work on this layer, they use protocols that work at L7! Examples of protocols: DHCP, DNS, HTTP, SNMP, FTP, TFTP, SMTP The Presentation Layer (L6) - correct answers Responsible for translation, conversion, compression and encryption. It helps the Application Layer process and shows a message. Examples: JPEG, GIF, MIDI, ASCII The Session Layer (L5) - correct answers Keeps an eye on all sessions and downloads and makes sure that a message arrives at the correct place. This layer manages connections (opens and closes sessions). Works very close with the Transport Layer. The Transport layer (L4) - correct answers TCP UDP TCP - correct answers Connection-oriented Reliable (acknowledgments and sequence numbers) Flow Control, windowing Stream oriented Slow, a bigger header (20 bytes) Used for reliable services: HTTP, SSH, TELNET, SMTP etc. UDP - correct answers Connectionless Unreliable, no acknowledgments No retransmissions. Best-effort only Message oriented Smaller header (8 bytes), faster than TCP Examples: streaming music and video, VOIP, TFTP, SNMP, DNS Three-way handshake - correct answers syn syn/ack ack fin fin/ack ack Windowing window size - correct answers the amount of data before getting an acknowledgement source address - correct answers created by OS of the computer destination address - correct answers goes to specific protocol example: 80 HTTP it wants a website Port numbers - correct answers allows a device to identify a service or process 80 - correct answers http 20/21 - correct answers ftp 23 - correct answers telnet 25 - correct answers SMTP 110 - correct answersPOP3 443 - correct answers HTTPS 3389 - correct answers RDP (microsoft proprietary) You want to open a new session using FTP. Which protocol will be used between your PC and an FTP Server? - correct answers TCCP Which layer can you identify? "acknowledgements and port numbers" - correct answers Layer 4 Transport Layer Encryption is done at this layer - correct answersL6 Sessions TCP - correct answers Windowing is used by TCP to control the number of packets SMTP, TELNET, HTTP port numbers - correct answers25, 23, 80 The network Layer L3 - correct answers Routing and Routers (driver The Internet Control Message Protocol - correct answers ICMP: ping protocol that works for the network layer IP addresses - correct answers identify a device on the network it has to be a unique addres in every local area network IPv4-32bits, 4 octets IPv6- 128 bits 192.168.1 (reserved for network .7 (host) /24 (subnet mask) Class A - correct answers1-127 255.0.0.0 network mask /8 prefix 126 number of networks 16,777,214 number of hosts Class B - correct answers128-191 255.255.0.0 network mask /16 16,382 65,534 Class C - correct answers192-223 255.255.0.0 /24 2,097,150 254 D - correct answers224-239 multicast addresses E - correct answers240-254 restricted/experimental/do not use Private Ip addresses: IMPORTANT MEMORIZE - correct answers10.0.0.0-10.255.255.255 172.16.0.0-172.31.255.255 192.168.0.0-192.168.255.255 cannot be used on the internet (cannot be routed not network layer translation Class A subnet mask - correct answers255.0.0.0 Class B subnet mask - correct answers255.255.0.0 Class C subnet mask - correct answers255.255.255.0 Data Link Layer L2 - correct answers it is all about switches