`netstat`

学习地址：

• https://linuxtechlab.com/learn-use-netstat-with-examples/

learn netstat with example.

Netstat is a command line utility that tells us about all the tcp/udp/unix socket connections on our system. It provides list of all connections that are currently established or are in waiting state. This tool is extremely useful in identifying the port numbers on which an application is working and we can also make sure if an application is working or not on the port it is supposed to work.

Example

1. Checking all connections:

   1	$ netstat -a

2. Check all tcp connections:

   1	$ netstat -at

   Check all udp connections:

   1	$ netstat -au

   Checking all unix connections:

   1	$ nestat -ax

3. List process id and name (it can be combination with any other netstat option):

   1	$ netast -ap

4. List all port number without its name (it will perform any reverse lookup & produce output with only numbers.), used to speed up:

   1	$ netstat -an

   port such as 22 will be resolve as ssh if n option is not specify.

5. Print only listen port:

   1	$ netstat -l

6. Print networks stats:

   1	$ netstat -s

7. Print Interfaces stats:

   1	$ netstat -i

8. Display multicast group information:

   1	$ netstat -g

9. Display network routing information:

   1	$ netstat -r

10. To get continuous information:

    1	$ netstat -c