SS utility is used to investigate sockets. It is used to dump socket statistics to show information like netstat command. ss displays statistics for TCP, UDP, UNIX and raw sockets. It can display more TCP and state information.
In this short article, I am going to show ss command uses and examples.
ss command syntax
The command is simple to use. You can type ss with options and filters.
$ ss [options] [ FILTER ]
To get about command options and filter use,
$ ss --h
Man of ss command
You can get more about ss on it’s manual page. Type following command.
$ man ss
View all TCP/UDP/UNIX socket connection
To view all types of connection with sent and received byte, source and destination just use ss command as below.
Listing all listening tcp port
To list all listening address and services use -lt option.
$ ss -lt
To list all listening addresses and port use -ltn, here l is for listening, t for tcp and n for displaying port not service.
$ ss -ltn
View only UDP connection
To view UDP connections only use the -u option as shown below. -a display both listening and non-listening sockets.
$ ss -ua
View all TCP/UPD listening connection with username
This is the most important command. I also used it frequently. Here -t for tcp connection , u for UDP, l for listening, p for process using socket, a for all and n for listing port not service name.
In the following output, you can see user, pid and source, destination for the connection.
$ sudo ss -tulpan | grep -i list
Memory utilized by the socket
Sometimes we may need to see which socket is using how much memory. For this, use ss command with the -m option as below.
$ ss -mt
List IPv4 and IPv6 sockets
To see all ip4 connections use -4 and for ipv6 use -6.
$ ss -4
$ ss -6
Display summary of socket connection
To display summary of socket connection just use -s option. It shows Total established, closed orphaned, time wait connection.
$ ss -s
You got an idea how to monitor socket connection using ss command. These commands are frequently used while running your system or applications. Thank you for getting here.
Karim Buzdar holds a degree in telecommunication engineering and holds several sysadmin certifications including CCNA RS, SCP, and ACE. As an IT engineer and technical author, he writes for various websites.