A weird macOS bug is blocking new network connections after 49 days of uptime

macOS can block new network connections after 49 days of continuous uptime.

The issue is tied to a 32-bit integer overflow bug in the XNU kernel.

The TCP/IP timing counter reaches its limit after 49 days, 17 hours, 2 minutes, and 47.296 seconds.

A monotonicity guard keeps the clock from rolling over, so TIME_WAIT entries are not cleaned up and ephemeral ports are exhausted.

Existing connections and ICMP still work, restarting only helps temporarily, Apple has no official fix yet, and Photon is working on a workaround.