FILL BLANK What command list the aliases defined in the current Bash shell? (Specify only the command without any path or parameters.)
Correct Answer:
alias
Question 182
Which of the following IPv4 networks are reserved by IANA for private address assignment and private routing? (Choose three.)
Correct Answer: B,D,E
Question 183
What is true about the ntpdate command?
Correct Answer: C
The ntpdate command is a tool used to synchronize the system date and time with the NTP (Network Time Protocol) server(s) specified as arguments. It can be run manually as necessary to set the system clock, or it can be run from a cron script to periodically update the system clock. The ntpdate command has the following syntax: ntpdate [options] server [server ...] The ntpdate command obtains a number of samples from each server and applies a subset of the NTP clock filter and selection algorithms to select the best one. It then adjusts the system clock either by stepping it (if the offset is larger than 0.5 seconds) or by slewing it (if the offset is smaller than 0.5 seconds). The ntpdate command can also be used to query the date and time from a server without setting the system clock by using the -q option. The other statements are false because: * It is not the primary management command for the NTP time server. The primary management command for the NTP time server is ntpd, which is a daemon that runs continuously and disciplines the system clock using sophisticated algorithms. * It updates both the local system's date and time, not just the date. The ntpdate command sets the system date and time according to the configured timezone information. * It does not send the local system time to any remote NTP time servers. The ntpdate command only queries the time from the servers and does not transmit any time information to them. * It cannot be used by any user to set the user clock independently of the system clock. The ntpdate command must be run as root on the local host and it affects the system clock for all users. References: * Linux ntpdate Command Tutorial - LinuxTect * ntpdate - set the date and time via NTP * How to Use NTPDATE to Sync Time in Ubuntu Linux? - TheITBros
Question 184
Which of the following looks like a correct entry in the /etc/hosts file?
Correct Answer: A
Question 185
Which command, depending on its options, can display the open network connections, the routing tables, as well as network interface statistics. (Specify ONLY the command without any path or parameters.)
Correct Answer:
netstat, /bin/netstat, ss, /usr/bin/ss Explanation: The netstat command, meaning network statistics, is a command-line utility in the Linux system to display network configuration and activity, including network connections,routing tables, interface statistics, masquerade connections, and multicast memberships1. The netstat command can display different types of network data depending on the command line option selected. Some of the common options are: * -a: This option displays active TCP connections, TCP connections with the listening state, as well as UDP ports that are being listened to. * -r: This option displays the routing table information, which is a list of rules that determine where the packets are sent. * -i: This option displays the network interface information, such as the name, MTU, RX-OK, TX-OK, etc. * -s: This option displays the network statistics by protocol, such as TCP, UDP, ICMP, IP, etc. For example, to display the open network connections, one can run: netstat -a To display the routing table, one can run: netstat -r To display the network interface statistics, one can run: netstat -i To display the network statistics by protocol, one can run: netstat -s For more details and examples, please refer to the web search results1 or the question answering results2. References: https://netref.soe.ucsc.edu/node/7 https://bing.com/search?q=command+to+display+network+connections%2c+routing+tables%2c+and+interface+
