100-140 Question 226
Single answerA user reports that their computer cannot connect to a specific server over the network. As part of your troubleshooting process, you decide to use the 'netstat' command on the user's machine. Which 'netstat' output would help you determine if the computer is attempting to establish a connection to the server?
- A
A line showing the server's IP address with the state 'ESTABLISHED'
- B
A line showing the server's IP address with the state 'LISTEN'
- C
A line showing the server's IP address with the state 'SYN_SENT'
- D
A line showing the server's IP address with the protocol 'UDP'
Show answer and explanation
Correct answer: C
Explanation
The 'SYN_SENT' state in the 'netstat' output indicates that the user's computer is actively trying to establish a TCP connection with the server by sending a SYN packet. This state is key for determining if the connection attempt is being made, as it shows the initial handshake process is in progress but not yet complete.
- A. Incorrect.
An 'ESTABLISHED' state indicates that a connection has already been successfully established with the server, which does not help determine if the computer is still attempting to connect.
- B. Incorrect.
'LISTEN' is a state typically seen on servers waiting for incoming connections. This state would not appear on the user's computer when trying to connect to a remote server.
- C. Correct.
'SYN_SENT' indicates that the user's computer has sent a TCP SYN packet to the server and is waiting for a response, which helps confirm that the computer is attempting to establish a connection.
- D. Incorrect.
UDP is a connectionless protocol and does not have a state like 'SYN_SENT'. Identifying a 'UDP' protocol line does not help in troubleshooting a connection attempt to a server.