Two coordinated fixes for the same root cause: Postfix's smtpd_upstream_proxy_protocol
listener fatals on every HAProxy health probe with `smtpd_peer_hostaddr_to_sockaddr:
... Servname not supported for ai_socktype` — the daemon respawns get throttled by
postfix master, and real client connections that land mid-respawn time out. We saw
this as ~50% timeout rate on public 587 from inside the cluster.
Layer 1 (book-search) — stacks/ebooks/main.tf:
SMTP_HOST mail.viktorbarzin.me → mailserver.mailserver.svc.cluster.local
Internal services should use ClusterIP, not hairpin through pfSense+HAProxy.
12/12 OK in <28ms vs ~6/12 timeouts on the public path.
Layer 2 (pfSense HAProxy) — stacks/mailserver + scripts/pfsense-haproxy-bootstrap.php:
Add 3 non-PROXY healthcheck NodePorts to mailserver-proxy svc:
30145 → pod 25 (stock postscreen)
30146 → pod 465 (stock smtps)
30147 → pod 587 (stock submission)
HAProxy uses `port <healthcheck-nodeport>` (per-server in advanced field) to
redirect L4 health probes to those ports while real client traffic keeps
going to 30125-30128 with PROXY v2.
Result: 0 fatals/min (was 96), 30/30 probes OK on 587, e2e roundtrip 20.4s.
Inter dropped 120000 → 5000 since log-spam concern is gone.
`option smtpchk EHLO` was tried first but flapped against postscreen (multi-line
greet + DNSBL silence + anti-pre-greet detection trip HAProxy's parser → L7RSP).
Plain TCP accept-on-port check is sufficient for both submission and postscreen.
Updated docs/runbooks/mailserver-pfsense-haproxy.md to reflect the new healthcheck
path and mark the "Known warts" entry as resolved.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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