Nodes running inside WSL2 or Docker have a virtual network interface whose IP
(172.16-31.x.x) is not reachable from physical machines on the LAN. The UDP
socket probe for outbound IP returns this virtual IP, which gets registered with
the tracker — causing downstream pipeline hops to time out with "urlopen error
timed out".
_warn_virtual_network_ip() now prints a clear multi-line warning at startup
when the auto-detected advertise IP falls in 172.16.0.0/12, including the
fix: --advertise-host <LAN-ip>.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>