102-500 Exam Dumps : LPIC-1 Exam 102, Part 2 of 2, version 5.0

 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:

According to the RFC 19181, the Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IPv4 address space for private internets:

10.0.0.0 - 10.255.255.255 (10/8 prefix)

172.16.0.0 - 172.31.255.255 (172.16/12 prefix)

192.168.0.0 - 192.168.255.255 (192.168/16 prefix)

These address blocks are not globally routable and are intended for use within private networks, such as home, office, or campus networks. They can be assigned to any device that does not need to communicate directly with the public internet, or that can use network address translation (NAT) to do so. Private addresses allow for more efficient use of the limited IPv4 address space and reduce the need for public addresses.

The other options are not reserved for private use by IANA. Option A, 127.0.0.0/8, is reserved for loopback addresses, which are used to refer to the local host. Option C, 169.255.0.0/16, is a typo and should be 169.254.0.0/16, which is reserved for link-local addresses, which are used for automatic address configuration on a local network segment. Option F, 224.0.0.0/4, is reserved for multicast addresses, which are used for one-to-many communication.

References:

RFC 1918: Address Allocation for Private Internets - RFC Editor

IANA IPv4 Special-Purpose Address Registry

Private network - Wikipedia