Network Management common Commands (6/14)-netstat command detailed

The Netstat command is used to display various network-related information, such as network connections, routing tables, Interface states (Interface Statistics), masquerade connections, multicast members (multicast memberships), and so on.

-A or--all: Displays the socket;-a< network type > or--< network type in all connections;: Lists the relevant addresses in the network type connection;-C or--continuous: Continuously list network status ;-C or--cache: Displays the cache information for the router configuration,-E or--extend: Displays other relevant information about the network;-F or--fib: Show fib;-g or--groups: Displays the multi-broadcast feature group members list;-H or--  Help: online assistance;-I or--interfaces: Displays the Web interface information form;-L or--listening: Displays the Socket;-m or--masquerade of the server in the monitor: shows the spoofed network connection ;-N or--numeric: use the IP address directly, not through the domain name server;-N or--netlink or--symbolic: Displays the symbolic connection name of the network hardware peripheral device;-O or--timers: Display timer ;-P or--programs: shows the program identification code and program name of the socket being used;-R or--route: Display routing table;-s or--statistice: Display network work information statistics ;-T or--tcp: Displays the connection status of the TCP transport protocol;-U or--UDP: Displays the connection status of the UDP transport protocol;-V or--verbose: Displays the instruction execution process;- V or--version: Displays version information; W or--raw: Displays the connection status of the raw transport protocol,-X or--unix: The effect of this parameter is the same as specifying the "-a Unix" parameter,--ip or--inet: The effect of this parameter is the same as specifying the "-a inet" parameter. 

Instance

List all ports (both listening and not listening)

Netstat-a     #列出所有端口netstat-at    #列出所有tcp端口netstat-au    #列出所有udp端口                             

List all Sockets in the listening state

Netstat-l        #只显示监听端口netstat-lt       #只列出所有监听 TCP port netstat-lu       #只列出所有监听 UDP port netstat-lx       #只列出所有监听 UNIX Port

Show statistics for each protocol

Netstat-s   Display statistics for all ports netstat-st   display statistics for TCP ports netstat-su   displays statistics for UDP ports

Show PID and process name in netstat output

Netstat-pt

hosts, ports and usernames (host, port or user) are not displayed in the Netstat output

When you don't want to let the host, port and user name display, use Netstat-n. Numbers will be used instead of those names.

The output can also be accelerated because there is no comparison query.

# Netstat-an

If you just don't want one of these three names to be displayed, use the following command

# netsat-a--numeric-ports
# netsat-a--numeric-hosts
# netsat-a--numeric-users

6. Continuous output of netstat information

Netstat will output network information every second. -C

9. Find out which port the program is running on

Not all processes can be found, no permissions will not be displayed, use root permissions to view all the information.

# Netstat-ap | grep ssh
TCP        1      0 dev-db:ssh           101.174.100.22:39213        close_wait  -
TCP        1      0 dev-db:ssh           101.174.100.22:57643        close_wait  -

Locate the process running on the specified port

# Netstat-an | grep ': 80 '

10. Display the list of network interfaces

# netstat-i

IP and TCP Analysis

To view the most connected IP addresses for a service port:

Sort-nr

TCP Various status lists:

Netstat-nt | Grep-e 127.0.0.1-e 0.0.0.0-e.:::-V | awk '/^tcp/{++state[$NF]} END {for (I in State) print I, "\ T", state[i]} '

View the number of phpcgi processes, and if they are close to the preset, they are not enough and need to be increased:

Netstat-anpo | grep "wc-l　　　　

Network Management common Commands (6/14)-netstat command detailed