Netstat output with boost::Asio - sockets

Question

I have created an asio server with acceptor:
m_acceptor(m_ios, asio::ip::tcp::endpoint(asio::ip::address_v4::any(), port_num)
where port number is 3333
At this point, the netstat -antup command shows :
13:tcp 0 0 0.0.0.0:3333 0.0.0.0:* LISTEN 26566/./test
So, I believe this means that local address 0 0.0.0.0:3333 is ready to listen to any connection on port 3333
After this, I start the client which creates the endpoint to ip : 127.0.0.1 and port 3333
After this, the netstat output is:
tcp 0 0 0.0.0.0:3333 0.0.0.0:* LISTEN 26566/./test
tcp 0 0 127.0.0.1:3333 127.0.0.1:46675 ESTABLISHED 26566/./test
tcp 0 0 127.0.0.1:46675 127.0.0.1:3333 ESTABLISHED 26685/./test
Process 26566 is master process
Process 26685 is slave process
What I do not understand is what does the the port 46675 mean in the address shown above? This definitely represents the client side, but from where was this port number allocated to the client?
Does this mean that client has connected to port 3333 but the port from which it itself connects is 46675?

Answer 1

Does this mean that client has connected to port 3333 but the port from which it itself connects is 46675?
Basically. It describes the client endpoint. This is BSD/Posix sockets jargon.
What I do not understand is what does the the port 46675 mean in the address shown above? This definitely represents the client side, but from where was this port number allocated to the client?
It gets automatically chosen (by the TCP stack, usually in the kernel) from the local port range. E.g. on linux you can manipulate that range (if you have permission):
sudo sysctl -w net.ipv4.ip_local_port_range="60000 61000"
(Warning: don't do this unless you know what you're doing). See also https://en.wikipedia.org/wiki/Ephemeral_port