base-trixie: the image on Debian trixie, Postfix 3.10.13; Received: hidden on 465/587

The runtime base is debian:trixie-slim, the build stage golang:1.26-trixie:
Postfix 3.10.13 with upstream's 2026 security fixes up to the August
batch, libmilter 8.18.1, OpenSSL 3.5. Every citation of another program in
code, scripts and documents was re-read against the trixie sources
(dev/upstream; bookworm's kept in dev/upstream-bookworm) and updated;
development.md's cited-package table holds the trixie versions.

What the re-reading changed in behaviour:
- logtail: reject lines with sasl_method/sasl_username/sasl_sender
  (smtpd_check.c:1019-1026); cleanup's "removed (canceled)" forgets a
  port-25 id (cleanup_api.c:363-364).
- internal/postfix/retry.go reads postconf's stdout only: since 3.9 a
  deprecated-parameter warning on stderr made one value too many and the
  panel fell back to the compiled-in retry policy.
- logrotate-loop.sh: logrotate 3.22 exits 1 when it ignores a config;
  the loop refuses on that output whatever the status.
- postfix-config.sh: cyrus_sasl_config_path set explicitly (bookworm's
  07_sasl_config.diff is gone); maillog_file_permissions=0640; mynetworks
  explicit; Dockerfile: SYNC_CHROOT= in /etc/default/postfix,
  opendkim-tools dropped, openssl named, systemd-standalone-sysusers so
  cron does not bring the whole of systemd.
- The selfpost group is 10998, outside the system range 100-999: in
  trixie a package took 998 and the build failed (owner's decision:
  a conflict-free id, the distribution's own ids untouched). The
  entrypoint hands /data back by name when the user or the group differs.
  Guide, backup refusal text, help (design commit 68ec8b2), e2e.
- smtpd_hide_client_session=yes on smtps and submission (owner's
  decision): Received: names no client, TLS, login or protocol; port 25
  keeps the full header. e2e checks both.
- test/upstream/opendkim-probe.sh makes keys with openssl genrsa.

Tests: on the server, make e2e exit 0 (674 s, the image built on trixie),
go vet + go test 27 packages ok. CHANGELOG [Unreleased], guide,
architecture.md, security.md, roadmap.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

test/e2e/process_check.go

@@ -73,7 +73,7 @@ func parseSupervisorStatus(out string) map[string]string {
 // port 25: smtp/inet is absent from master.cf (Debian's stock listener is
 // removed when INBOUND_RELAY_ENABLE is not true). For an absent service
 // postconf -M prints nothing on stdout and "warning: unmatched request" on
-// stderr (Postfix 3.7.11, src/postconf/postconf_master.c,
+// stderr (Postfix 3.10.13, src/postconf/postconf_master.c,
 // pcf_show_master_entries()).
 func checkInboundRelayOff(s *stack) error {
 	out, err := s.execIn("selfpost", "postconf", "-M", "smtp/inet")
@@ -90,7 +90,7 @@ func checkInboundRelayOff(s *stack) error {
 // checkCitedPackageVersions compares the Debian packages the image runs with
 // the versions their sources were read at (docs/development.md, the table
 // between the cited-package-versions markers). The image installs unpinned
-// from a moving bookworm, so a point release changes them on a rebuild
+// from a moving trixie, so a point release changes them on a rebuild
 // without anyone reading what changed (assumptions C-D1).
 func checkCitedPackageVersions(s *stack) error {
 	doc, err := os.ReadFile(filepath.Join(s.repoRoot, "docs", "development.md"))