Reversed the wrong conclusion in 46bba0d. The vanilla L4D2 logaddress
UDP path is NOT broken — proved by retesting with destination
172.30.0.5:28000 (wireguard IP) which yielded 8 properly framed HL
Log Standard packets in 12s including real game events.
Root cause: the Source engine silently drops logaddress destinations
in 127.0.0.0/8. Registration succeeds and the cvar API reports
"logging to: udp" but sendto is never called for loopback. Every
other L4D2 stats deployment (multiple production HLstatsX:CE
instances) puts the collector on a separate host or interface IP
and never hits this.
Defaults: LOG_LISTENER_BIND=0.0.0.0:28000 (accept on any interface);
LOG_LISTENER_ADDR="" (production must set via web.env to the host's
non-loopback IP). Empty default = safe no-op for dev. The kernel's
same-host routing optimization keeps the traffic on lo internally
but the packet's destination IP must not literally be in 127/8.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
122e0abddd