TCP hole punching for Bitcoin nodes behind home NATs?

Option 6 depends on the arrival of address self-announcements at both home-nodes. This introduces a significant reliability concern because the process is susceptible to delays or failures in message delivery. Relying on both nodes to receive these announcements increases the chances that connections might not be established as intended, especially in dynamic or unreliable network environments.

The existing address relay algorithms are tailored for long-lived addresses, which are announced infrequently and stored for extended periods to facilitate repeated usage. These algorithms are ill-suited for handling hole-punching data, which is inherently short-lived and loses validity immediately after the first successful connection. The fundamental mismatch between the longevity requirements of current relay schemes and the transient nature of hole-punching information makes their application problematic in scenarios where rapid and temporary connectivity is necessary.