The Linux netstat command is used to display network status.
Use the NETSTAT directive to let you know the network situation of the entire Linux system.
In the Internet RFC standard, netstat is defined as: Netstat is a program that accesses the state of the network connection and its associated information in the kernel, and it provides reports on TCP connections, TCP and UDP snooping, and process memory management. Netstat is a console command and is a very useful tool for monitoring TCP/IP networks, which can display routing tables, actual network connections, and status information for each network interface device. The netstat is used to display statistics related to IP, TCP, UDP, and ICMP protocols, and is typically used to verify the network connectivity of each port on the machine. If your computer sometimes receives data packets that cause error data or failures, you don't have to be surprised that TCP/IP can tolerate these types of errors and be able to automatically re-send packets. But if the cumulative number of errors accounts for a significant percentage of the IP datagram received, or if its number is increasing rapidly, then you should use Netstat to find out why these situations occur. Netstat-an are generally used to display all connected ports and are represented by numbers. The function of the
netstat command is to display network connections, routing tables, and network interface information to let users know which network connections are in operation.
[1] When used without parameters,netstat displays the active TCP connection.Netstat-nlupt
"Linux" netstat detailed