https://os.husseinnasser.com

Why Windows Kernel connects slower than Linux

I explore the behavior of TCP/IP stack in Windows kernel when it receives a RST from the backend server especially when the host is available but the port we are trying to connect to is not. This behavior is exacerbated by having both IPv6 and IPv4 and if the happy eye ball protocol is in place where IPv6 is favorable.

0:00 Intro

0:30 Fundamentals TCP/IP

3:00 Unreachable Port Behavior

6:00 Client Kernel Behavior (Linux vs Windows)

11:40 Slow TCP Connect on Windows

15:00 localhost, IPv6 and IPv4

20:00 Happy Eyeballs

28:00 Registry keys to change the behavior

31:00 Port Unreachable vs Host Unreachable

https://daniel.haxx.se/blog/2024/08/14/slow-tcp-connect-on-windows/