Number of concurrent server connections?

Question

linux

Wrote a simple SMTP server in python (it doesn't matter), through the library

socket

, later I came across an article on Habré https://habrahabr.ru/post/123154/ I had one difficult (for me) question: how do servers support a huge number of simultaneous connections (tcp) if the number of sockets is limited? (65535)

Answer 1

it is not the number of sockets that is limited, but the number of own ports per IP
do not confuse outgoing connections with incoming
ones, when outgoing connections are "consumed" localIP:localPort pairs,
while incoming there is always one localIP:localPort pair

Answer 2

Создается несколько IP адресов. Можно даже на той же самой сетевушке несколько интерфейсов. На каждом по 65534 сокетов.

Answer 3

Там же в комментариях и есть разъяснение "как такое возможно".