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If you want to access the socket related information of your system, the first utility that most of the people think of is netstat. But if you want to get more information, you can use ss command for that purpose.

ss command is used to dump the socket statistics and display the information. It works similar to netstat command, but it is faster than that. You can also display even more TCP and state information than most other tools using ss command.

In this tutorial, we will explain the usage of ss command with the help of multiple examples.

General Syntax

Following is the general syntax of the ss command

[email protected]:~$ ss [options] [ FILTER ]

Displaying All Sockets With Established Connections

You can run the simple ss command without any option to display the list of all the sockets with established connections.

[email protected]:~$ ss

NetidState  Recv-Q Send-Q                               Local Address:Port                                     Peer Address:Port                                
u_strESTAB  0      0                               /run/user/1000/bus 23614                                               * 22709                               
u_strESTAB  0      0                                                * 20958                                               * 22366                               
u_strESTAB  0      0                  /var/run/dbus/system_bus_socket 16311                                               * 16310                               
u_strESTAB  0      0                                                * 15593                                               * 16959                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 24104                                               * 25309                               
u_strESTAB  0      0                  /var/run/dbus/system_bus_socket 19421                                               * 17398                               
u_strESTAB  0      0                                                * 30149                                               * 29296                               
u_strESTAB  0      0                                                * 25679                                               * 24115                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 30145                                               * 30144                               
u_strESTAB  0      0                                                * 28681                                               * 27327                               
u_strESTAB  0      0                                                * 23165                                               * 23751                               
u_strESTAB  0      0                              @/tmp/dbus-eflm2M2S 21233                                               * 21232                               
u_strESTAB  0      0                  /var/run/dbus/system_bus_socket 22712                                               * 22711                               
u_strESTAB  0      0                            @/tmp/dbus-iwLZdza2Tx 20430                                               * 20821                               
u_strESTAB  0      0                                                * 22550                                               * 22174                               
u_strESTAB  0      0                                                * 25365                                               * 24152                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 19595                                               * 17359                               
u_strESTAB  0      0                               /run/user/1000/bus 27635                                               * 30150                               
u_strESTAB  0      0                                                * 25665                                               * 23283                               
u_strESTAB  0      0                               /run/user/1000/bus 26151                                               * 24354                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 21252                                               * 22838                               
u_strESTAB  0      0                               /run/user/1000/bus 23607                                               * 21213                               
u_strESTAB  0      0                               /run/user/1000/bus 20398                                               * 20813                               
u_strESTAB  0      0                              @/tmp/dbus-lP6d8qhj 20724                                               * 21770                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 19547                                               * 18817                               
u_strESTAB  0      0                  /var/run/dbus/system_bus_socket 16958                                               * 15587                               
u_strESTAB  0      0                                                * 25258                                               * 23259                               

This is a sample output of the command.

Suppressing The Header Line In Output

If you want to suppress the header line in the output of the command, you can use the option -H with the ss comamnd.

[email protected]:~$ ss -H

u_strESTAB  0      0                               /run/user/1000/bus 23614                                               * 22709                               
u_strESTAB  0      0                                                * 20958                                               * 22366                               
u_strESTAB  0      0                  /var/run/dbus/system_bus_socket 16311                                               * 16310                               
u_strESTAB  0      0                                                * 15593                                               * 16959                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 24104                                               * 25309                               
u_strESTAB  0      0                  /var/run/dbus/system_bus_socket 19421                                               * 17398                               
u_strESTAB  0      0                                                * 30149                                               * 29296                               
u_strESTAB  0      0                                                * 25679                                               * 24115                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 30145                                               * 30144                               
u_strESTAB  0      0                                                * 28681                                               * 27327                               
u_strESTAB  0      0                                                * 23165                                               * 23751                               
u_strESTAB  0      0                              @/tmp/dbus-eflm2M2S 21233                                               * 21232                               
u_strESTAB  0      0                  /var/run/dbus/system_bus_socket 22712                                               * 22711                               
u_strESTAB  0      0                            @/tmp/dbus-iwLZdza2Tx 20430                                               * 20821                               
u_strESTAB  0      0                                                * 22550                                               * 22174                               
u_strESTAB  0      0                                                * 25365                                               * 24152                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 19595                                               * 17359                               
u_strESTAB  0      0                               /run/user/1000/bus 27635                                               * 30150                               
u_strESTAB  0      0                                                * 25665                                               * 23283                               
u_strESTAB  0      0                               /run/user/1000/bus 26151                                               * 24354                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 21252                                               * 22838                               
u_strESTAB  0      0                               /run/user/1000/bus 23607                                               * 21213                               
u_strESTAB  0      0                               /run/user/1000/bus 20398                                               * 20813                               
u_strESTAB  0      0                              @/tmp/dbus-lP6d8qhj 20724                                               * 21770                               
u_strESTAB  0      0                      /run/systemd/journal/stdout 19547                                               * 18817                               
u_strESTAB  0      0                  /var/run/dbus/system_bus_socket 16958                                               * 15587                               
u_strESTAB  0      0                                                * 25258                                               * 23259                               

Displaying Only tcp Connections

If you want to display only tcp connections in the output of the command, you can use the option -t with the ss comamnd.

[email protected]:~$ ss -t

Displaying Only udp Connections

If you want to display only udp connections in the output of the command, you can use the option -u with the ss comamnd.

[email protected]:~$ ss -u

Displaying Only unix Connections

If you want to display only unix connections in the output of the command, you can use the option -x with the ss comamnd.

[email protected]:~$ ss -x

Displaying All The Sockets (Listening & Non-Listening)

If you want to display all the sockets of your system (listening and non-listening), you can use the option -a with the ss comamnd.

[email protected]:~$ ss -a

Displaying Only Listening Sockets

If you want to display only the listening sockets, you can use the option -l with the ss comamnd.

[email protected]:~$ ss -l

Displaying The Processes Using The Sockets

If you want to display the processes that are using the sockets, you can use the option -p with the ss comamnd.

[email protected]:~$ ss -p

Netid             State               Recv-Q              Send-Q                                                         Local Address:Port                                 Peer Address:Port                                                                                                                                                                                                                           
u_str             ESTAB               0                   0                                                                          * 25258                                           * 23259               users:(("gsd-screensaver",pid=1318,fd=2))                                                                                                                                                                  
u_str             ESTAB               0                   0                                                                          * 31015                                           * 29464               users:(("gnome-software",pid=2178,fd=18))                                                                                                                                                                  
u_str             ESTAB               0                   0                                                      @/tmp/dbus-iwLZdza2Tx 29296                                           * 30149               users:(("dbus-daemon",pid=1036,fd=20))                                                                                                                                                                     
u_str             ESTAB               0                   0                                                                          * 25680                                           * 24118               users:(("gsd-xsettings",pid=1341,fd=8))                                                                                                                                                                    
u_str             ESTAB               0                   0                                                                          * 21469                                           * 23264               users:(("gsd-sharing",pid=1323,fd=1))               

Displaying The Summary Info

If you don’t want the default output of the command, you can display a short summary of the output using the option -s with the ss comamnd.

[email protected]:~$ ss -s

Total: 674 (kernel 0)
TCP:   3 (estab 0, closed 0, orphaned 0, synrecv 0, timewait 0/0), ports 0

Transport Total     IP        IPv6
*	  0         -         -        
RAW	  1         0         1        
UDP	  7         5         2        
TCP	  3         2         1        
INET	  11        7         4        
FRAG	  0         0         0    

Displaying Only IPv4/IPv6 Sockets

If you want to display only the IPv4 sockets, you can use the option -4 with the ss comamnd.

[email protected]:~$ ss -4

If you want to display only the IPv6 sockets, you can use the option -6 with the ss comamnd.

[email protected]:~$ ss -6

Not Resolving The IP Addresses To Hostnames

If you want to get a faster output from the command, you can use the option -n with the ss comamnd to prevent the command to resolve the IP addresses into the hostnames. But this will prevent resolution of port numbers as well.

[email protected]posts:~$ ss -n