Table of Contents
How many processes can use a port?
Only one process can listen for new connections. You’ll get an “address already used” error if more than one processes attempt to claim the same port.
Can multiple applications listen to the same port?
Two applications can certainly listen on the same port. But the socket for each connection can not be bound to the same IP address on the same port.
Can multiple processes bind to same port?
Yes, different applications can bind to the same port on different transport protocols. They can also open the same port on the same protocol but different IP addresses.
How many connections can you have on the same port?
Irrespective of stateful or stateless protocols, two clients can connect to same server port because for each client we can assign a different socket (as client IP will definitely differ). Same client can also have two sockets connecting to same server port – since such sockets differ by SRC-PORT .
Sockets can be shared among threads in a given process without using the WSADuplicateSocket function because a socket descriptor is valid in all threads of a process. A process can call closesocket on a duplicated socket and the descriptor will become deallocated.
How many ports can an IP address have?
65,535
Ports work the same way. You have an IP address, and then many ports on that IP address. When I say many, I mean many. You can have a total of 65,535 TCP Ports and another 65,535 UDP ports.
Can multiple threads listening on same port?
Multiple servers (processes or threads) can bind to the same port if they each set the option as follows: With TCP sockets, it allows multiple listening sockets—normally each in a different thread—to be bound to the same port. Each thread can then accept incoming connections on the port by calling accept().
How many sockets can a port have?
For most socket interfaces, the maximum number of sockets allowed per each connection between an application and the TCP/IP sockets interface is 65535.
How many sockets does a TCP server need?
So the answer to your question is that only one listen socket is needed, but new sockets will be created as clients connect (and removed as they disconnect). The limit of sockets (file descriptors) than an application can create is controlled by the OS.
Do threads have the same process ID?
Thread and process have the same PID. Whenever a process spawns a thread or multiple threads, all of them (including process) have the same PID. The difference will be in their TGID (Thread group ID). Threads are identifying by their unique ID called TGID.
What is So_reuseport?
SO_REUSEPORT is what most people would expect SO_REUSEADDR to be. Basically, SO_REUSEPORT allows you to bind an arbitrary number of sockets to exactly the same source address and port as long as all prior bound sockets also had SO_REUSEPORT set before they were bound.