6.1 Lesson Review

Which netstat switch is used to filter sockets by IPv4 or IPv6 addresses on Linux?

-4 or -6 In Linux, the -4 switch filters for IPv4 addresses, and -6 filters for IPv6 addresses when using the netstat command.

You've recently installed a new Windows server. To ensure system time accuracy, you've loaded an application that synchronizes the hardware clock on the server with an external time source on the Internet. Now you must configure your network firewall to allow time synchronization traffic through. Which of the following ports are you MOST likely to open on the firewall?

123 Port 123 is used by the Network Time Protocol (NTP), which is responsible for synchronizing time across devices. Opening this port allows your server to synchronize with an external time source.

UDP is particularly suitable for which type of applications?

Applications that send small amounts of data and do not require acknowledgment UDP is suitable for applications that prioritize speed over reliability, such as those sending small data packets without requiring guaranteed delivery or acknowledgment, like video streaming or online gaming.

How is a connection uniquely identified in a TCP/IP network?

By the combination of server port and IP address and client port and IP address In a TCP/IP network, each connection is uniquely identified by the four-tuple consisting of the client IP address, client port, server IP address, and server port. This combination ensures that each connection is distinct, even if multiple connections are made between the same client and server.

Which TCP flag is used by both the client and server to indicate that they want to close the connection?

FIN The FIN flag is used by both the client and server to signal the desire to close a TCP connection gracefully. Each side sends a FIN to indicate that it has finished sending data.

Which statement BEST describes the use of port numbers in TCP/IP networking?

Port numbers are used in conjunction with IP addresses to direct packets to specific services or applications. Port numbers help identify which application or service on a device should handle incoming packets. They work alongside IP addresses to ensure data reaches the correct program or service. 4o

Which TCP flag is set by the client to initiate the three-way handshake?

SYN The SYN flag is set by the client to initiate the three-way handshake, marking the start of a new TCP connection.

A network administrator is looking at packet captures from the network and trying to isolate email traffic. Which of the following should the network administrator include? (Select two.)

TCP 143 and TCP 25 TCP 25 is used by SMTP (Simple Mail Transfer Protocol) for sending emails. TCP 143 is used by IMAP (Internet Message Access Protocol) for retrieving emails.

What might cause a host to send a reset (RST) segment during a TCP session?

The host decides to abruptly end the session. A reset (RST) segment is sent to immediately terminate a TCP session, typically due to an error or unexpected condition, signaling that the connection should be closed abruptly.

What is the purpose of a socket in the context of network communications?

To serve as a unique identifier for a network connection In network communications, a socket uniquely identifies a connection by combining the IP address and port number of both the client and server, enabling communication between specific applications on each device. 4o

Which protocols and port numbers are used by DHCP? (Select two.)

UDP 67 and UDP 68 UDP 67 is used by the DHCP server to receive client requests. UDP 68 is used by the DHCP client to receive responses from the server. DHCP relies on these ports to assign IP addresses dynamically.

Your computer is sharing information with a remote computer using the TCP/IP protocol. Suddenly, the connection stops working and appears to hang. Which command can you use to check the state of ports on your computer?

netstat The netstat command allows you to check the state of ports and active connections on your computer, helping to diagnose issues in the connection.

Which command would you use to show listening and established Internet connections (TCP and UDP) only?

netstat -tua The command netstat -tua shows only listening and established Internet connections for TCP (-t) and UDP (-u) protocols.

What does TCP use to divide data from the Application layer?

segments

What layer of the OSI model does the Transmission Control Protocol (TCP) operate at?

transport layer