When TCP sockets refuse to die

What this post added

This post significantly deepens the understanding of process management by focusing on the low-level network behavior of TCP sockets. It addresses the problem of 'lingering' TCP sockets, which can prevent graceful connection closure and impact service reliability. The post details the mechanics of TCP timeouts in different connection states (SYN-SENT, SYN-RECV, ESTABLISHED) and explains the crucial roles of TCP keepalives and the `TCP_USER_TIMEOUT` socket option. It provides practical examples and debugging insights, highlighting how these mechanisms ensure that idle or broken connections are eventually terminated, thereby contributing to more robust and resilient system operations, particularly relevant for services like Cloudflare Spectrum.