diff --git a/CHANGELOG.md b/CHANGELOG.md
index 78aa307..0675280 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -216,6 +216,17 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
   showq service: Permission denied"), the Queue card said "Could not be read"
   and the queue page had no listing. Present since the persistent queue of
   1.3.0; mail flow was not affected. The e2e suite opens the queue page now.
+- **Port 25 answers again with DMARC report ingest on.** The generated
+  `master.cf` gave the port-25 service `-o smtpd_recipient_restrictions=
+  check_recipient_access texthash:…,…` with a space in the value; Postfix
+  cuts a service line at whitespace, so `smtpd` was started with a stray
+  argument and died with "fatal: unexpected command-line argument" on every
+  connection - no inbound relay and no DMARC reports were accepted while
+  `DMARC_REPORTS_ENABLE=true`, although `postfix check` and the suite were
+  silent. The list is written with commas only, the generator refuses a
+  value with whitespace, and the e2e check asks Postfix what it reads.
+  Present since DMARC ingest was fitted into the 1.9.1 fix of the same
+  stanza.
 - Overview's Processes card counts the programs that are meant to stay up
   ("6 of 6 running"); the idle one-shot `postfix-reload` was counted as
   running. The Milter sockets card no longer clips its second line with three
diff --git a/build/postfix-config.sh b/build/postfix-config.sh
index f0aaa01..48783ae 100644
--- a/build/postfix-config.sh
+++ b/build/postfix-config.sh
@@ -13,12 +13,25 @@
 # a fixed literal or a container environment variable.
 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.
+# Sets one -o option of the smtp/inet (port 25) service by patching its stanza.
+#
+# A master.cf -o value must not contain whitespace: master splits the line on
+# it, so "-o name=check_recipient_access texthash:/x,reject" reaches smtpd as
+# the option "name=check_recipient_access" plus a stray argument, and smtpd dies
+# at start with "fatal: unexpected command-line argument" - port 25 then
+# answers nobody. (postconf -P refuses such values for the same reason.) Postfix
+# splits a restriction list on commas as well as on whitespace, so every value
+# passed here is written with commas only; a value with whitespace is a bug in
+# this script and stops the container.
 master_cf_set_smtp_inet_o() {
 	param="$1"
 	value="$2"
+	case "$value" in
+		*[[:space:]]*)
+			echo "FATAL: master.cf -o ${param} would contain whitespace: ${value}" >&2
+			exit 1
+			;;
+	esac
 	awk -v p="$param" -v v="$value" '
 		/^smtp[ \t]+inet[ \t]/ && !done {
 			print
@@ -284,7 +297,9 @@ if [ "${INBOUND_RELAY_ENABLE}" = "true" ] || [ "${DMARC_REPORTS_ENABLE}" = "true
 			RELAY_DOMAINS_SETTING="texthash:${DMARC_RELAY_DOMAINS_MAP}"
 			TRANSPORT_SETTING="texthash:${DMARC_TRANSPORT_MAP}"
 		fi
-		RECIPIENT_RESTRICTIONS="check_recipient_access texthash:${DMARC_RECIPIENTS_MAP},${RECIPIENT_RESTRICTIONS}"
+		# Comma, not a space, between check_recipient_access and its table: see
+		# master_cf_set_smtp_inet_o.
+		RECIPIENT_RESTRICTIONS="check_recipient_access,texthash:${DMARC_RECIPIENTS_MAP},${RECIPIENT_RESTRICTIONS}"
 	fi
 	postconf -e \
 		"relay_domains=${RELAY_DOMAINS_SETTING}" \
diff --git a/test/e2e/port25_config_check.go b/test/e2e/port25_config_check.go
index 44b82d8..faf0d03 100644
--- a/test/e2e/port25_config_check.go
+++ b/test/e2e/port25_config_check.go
@@ -47,7 +47,7 @@ var port25Cases = []port25Case{
 			"DMARC_REPORTS_ENABLE=true",
 		},
 		check: []optionCheck{
-			{param: "smtpd_recipient_restrictions", contains: "check_recipient_access texthash:/data/postfix/dmarc_recipients,reject", wantExact: true},
+			{param: "smtpd_recipient_restrictions", contains: "check_recipient_access,texthash:/data/postfix/dmarc_recipients,reject", wantExact: true},
 			{param: "smtpd_milters", contains: "", wantExact: true},
 		},
 	},
@@ -58,7 +58,7 @@ var port25Cases = []port25Case{
 			"DMARC_REPORTS_ENABLE=true",
 		},
 		check: []optionCheck{
-			{param: "smtpd_recipient_restrictions", contains: "check_recipient_access texthash:/data/postfix/dmarc_recipients,reject_unauth_destination,reject_unlisted_recipient", wantExact: true},
+			{param: "smtpd_recipient_restrictions", contains: "check_recipient_access,texthash:/data/postfix/dmarc_recipients,reject_unauth_destination,reject_unlisted_recipient", wantExact: true},
 			{param: "smtpd_milters", contains: "", wantExact: true},
 		},
 	},
@@ -116,6 +116,18 @@ func checkPort25ConfigCombinations(s *stack) error {
 			case !c.wantExact && !strings.Contains(got, c.contains):
 				return fmt.Errorf("%s: -o %s = %q, want it to contain %q", tc.name, c.param, got, c.contains)
 			}
+			// What the file says is not yet what Postfix reads: master splits
+			// a service line on whitespace, so a value with a space in it is
+			// cut at the space and the rest becomes a stray smtpd argument
+			// ("fatal: unexpected command-line argument", port 25 dead while
+			// `postfix check` stays silent). Ask Postfix itself.
+			seen, err := s.execIn("selfpost", "postconf", "-Ph", "smtp/inet/"+c.param)
+			if err != nil {
+				return fmt.Errorf("%s: postconf -P smtp/inet/%s: %v\n%s", tc.name, c.param, err, seen)
+			}
+			if strings.TrimSpace(seen) != got {
+				return fmt.Errorf("%s: master.cf has -o %s = %q but Postfix reads %q - the value contains whitespace", tc.name, c.param, got, strings.TrimSpace(seen))
+			}
 		}
 	}