sockets

What is a socket in TCP/IP ?
- A socket is just a logical endpoint for communication. They exist on the transport layer. 
- You can send and receive things on a socket, you can bind and listen to a socket. 
- A socket is specific to a protocol, machine, and port, and is addressed as such in the header of a packet.
-  is a means of two way ("duplex") communication, that means you can write to and read from the same socket, 
 and you do not need two separate sockets for a two-way communication.
-  are one possible way of inter-process communication (shared memory and pipes being examples of alternatives)
- At the same time, they are being used for "networking",
- For udp or tcp over IP, a socket address is the combination of an IP address and a port number.
- A socket can have a LISTEN state or an ESTABLISHED state
- A socket is a window between your server/operating system that serves you and the inter net

netstat -xl

ss -x state listening

What is a socket file in linux?
- A socket is a special file used for inter-process communication. These enable communication between two processes. 
- In addition to sending data, processes can send file descriptors across a Unix domain socket connection using the sendmsg() 
- and recvmsg() system.
- are one possible way of inter-process communication (shared memory and pipes being examples of alternatives)

# list all sockets on your machine
find / -typs s