fix: port-25 Postfix config when inbound, DMARC, or antispam are enabled

postconf -P cannot set master.cf -o values with whitespace; patch smtp/inet
directly and route DMARC ingest through a dmarc-ingest symlink.

Co-authored-by: Cursor <cursoragent@cursor.com>

CHANGELOG.md

@@ -33,6 +33,15 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
   and [docs/architecture.md](docs/architecture.md) link to the new file;
   `schema-squash` defers gate thresholds to it instead of a stale v5 snapshot.
 
+### Fixed
+
+- `build/postfix-config.sh`: enabling inbound relay, DMARC ingest, and/or the
+  inbound antispam milter no longer crash-loops on start — `postconf -P` cannot
+  set `master.cf` `-o` values that contain whitespace, so port-25
+  `smtpd_recipient_restrictions` and `smtpd_milters` are patched directly; DMARC
+  pipe `argv` uses a `dmarc-ingest` symlink instead of `panel -dmarc-ingest`.
+
+## [1.9.0] - 2026-08-18
 
 Application sending controls: client IP allow-list for authorization, and
 level-2 rate limits that override the domain ceiling per application.

build/postfix-config.sh

@@ -13,6 +13,37 @@
 # a fixed literal or a container environment variable (spec 7.6.3).
 set -eu
 
+# postconf -P refuses master.cf -o values that contain whitespace; inbound port
+# 25 needs restriction lists and milter specs that include spaces. Patch the
+# smtp/inet service stanza directly instead.
+master_cf_set_smtp_inet_o() {
+	param="$1"
+	value="$2"
+	awk -v p="$param" -v v="$value" '
+		/^smtp[ \t]+inet[ \t]/ && !done {
+			print
+			print "    -o " p "=" v
+			done = 1
+			in_smtp_inet = 1
+			next
+		}
+		in_smtp_inet && /^[ \t]+-o / {
+			line = $0
+			sub(/^[ \t]+-o /, "", line)
+			eq = index(line, "=")
+			on = substr(line, 1, eq - 1)
+			if (on == p) {
+				next
+			}
+		}
+		in_smtp_inet && /^[^ \t#-]/ {
+			in_smtp_inet = 0
+		}
+		{ print }
+	' /etc/postfix/master.cf > /etc/postfix/master.cf.new
+	mv /etc/postfix/master.cf.new /etc/postfix/master.cf
+}
+
 # --- environment knobs (spec 8) ----------------------------------------------
 # Server hostname: used as HELO name AND, crucially, as the Cyrus SASL realm the
 # sasldb2 accounts are looked up under. The panel creates accounts under realm
@@ -241,11 +272,12 @@ if [ "${INBOUND_RELAY_ENABLE}" = "true" ] || [ "${DMARC_REPORTS_ENABLE}" = "true
 		for f in "$DMARC_RECIPIENTS_MAP" "$DMARC_TRANSPORT_MAP" "$DMARC_RELAY_DOMAINS_MAP"; do
 			[ -e "$f" ] || : > "$f"
 		done
+		ln -sf /usr/local/bin/panel /usr/local/bin/dmarc-ingest
 		postconf -M "dmarc-ingest/unix-pipe=dmarc-ingest unix - n n - - pipe"
 		postconf -P \
 			"dmarc-ingest/unix-pipe/flags=Rq" \
 			"dmarc-ingest/unix-pipe/user=panel" \
-			"dmarc-ingest/unix-pipe/argv=/usr/local/bin/panel -dmarc-ingest"
+			"dmarc-ingest/unix-pipe/argv=/usr/local/bin/dmarc-ingest"
 		if [ -n "$RELAY_DOMAINS_SETTING" ]; then
 			RELAY_DOMAINS_SETTING="${RELAY_DOMAINS_SETTING} texthash:${DMARC_RELAY_DOMAINS_MAP}"
 			TRANSPORT_SETTING="${TRANSPORT_SETTING} texthash:${DMARC_TRANSPORT_MAP}"
@@ -311,10 +343,12 @@ if [ "${INBOUND_RELAY_ENABLE}" = "true" ] || [ "${DMARC_REPORTS_ENABLE}" = "true
 		"smtp/inet/smtpd_sender_restrictions=" \
 		"smtp/inet/smtpd_client_restrictions=" \
 		"smtp/inet/smtpd_relay_restrictions=reject_unauth_destination" \
-		"smtp/inet/smtpd_recipient_restrictions=${RECIPIENT_RESTRICTIONS}" \
-		"smtp/inet/smtpd_milters=${INBOUND_MILTERS}" \
 		"smtp/inet/smtpd_client_message_rate_limit=${PORT25_RATE}" \
 		"smtp/inet/message_size_limit=${PORT25_SIZE}"
+	master_cf_set_smtp_inet_o smtpd_recipient_restrictions "${RECIPIENT_RESTRICTIONS}"
+	if [ -n "${INBOUND_MILTERS}" ]; then
+		master_cf_set_smtp_inet_o smtpd_milters "${INBOUND_MILTERS}"
+	fi
 else
 	postconf -MX "smtp/inet" 2>/dev/null || true
 	postconf -MX "dmarc-ingest/unix-pipe" 2>/dev/null || true