Question

In linux, netstat command tells us information of active sockets in system.

I understand that netstat uses /proc/net/tcp to acquire the system network information.

Since netstat man page says that netstat is obsolete, so we should use ‘ss’.

NOTE
   This program is obsolete.  Replacement for netstat is ss.   Replacement
   for  netstat -r is ip route.  Replacement for netstat -i is ip -s link.
   Replacement for netstat -g is ip maddr.

I have discovered that ss performs similar functionality but it does not use
/proc/net/tcp to acquire system network information.

Now I am curious how ss gets system network socket information?

Answer 1

It gets them from kernel space directly using Netlink which uses the classic sockets API.