diff --git a/deploy/railiance/Dockerfile b/deploy/railiance/Dockerfile
index 79c7708..1724228 100644
--- a/deploy/railiance/Dockerfile
+++ b/deploy/railiance/Dockerfile
@@ -2,7 +2,7 @@
 # Build from the repo root:  docker build -f deploy/railiance/Dockerfile .
 FROM debian:bookworm-slim
 RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-      postfix python3 python3-jsonschema ssl-cert ca-certificates && rm -rf /var/lib/apt/lists/*
+      postfix libsasl2-modules python3 python3-jsonschema ssl-cert ca-certificates && rm -rf /var/lib/apt/lists/*
 RUN useradd -r -s /usr/sbin/nologin mas
 COPY mas_core /app/mas_core
 COPY mas_gateway /app/mas_gateway
diff --git a/deploy/railiance/entrypoint.sh b/deploy/railiance/entrypoint.sh
index 5b1018b..2717d76 100644
--- a/deploy/railiance/entrypoint.sh
+++ b/deploy/railiance/entrypoint.sh
@@ -41,6 +41,28 @@ postconf -e \
   "smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem" \
   "smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key" \
   "inet_protocols=ipv4" "compatibility_level=3.6"
+# start-fg does not populate the chroot (no resolv.conf), so DNS fails inside
+# it: client rDNS shows "unknown" and a relayhost would not resolve. The
+# container already isolates Postfix, so run the daemons unchrooted.
+postconf -F '*/*/chroot = n'
+
+# Outbound replies (reply test). Port 25 out is blocked on railiance01, so
+# replies go through an authenticated submission relay, and only when its
+# credentials are mounted. Only loopback (the ticket service) may relay.
+# Without a relay all non-local mail fails fast instead of queueing.
+SMTP_ARG=""
+if [ -n "$MAS_RELAY" ] && [ -s /etc/mas-relay/username ]; then
+  printf '%s %s:%s\n' "$MAS_RELAY" "$(cat /etc/mas-relay/username)" \
+    "$(cat /etc/mas-relay/password)" > /etc/postfix/sasl_passwd
+  chmod 600 /etc/postfix/sasl_passwd && postmap /etc/postfix/sasl_passwd
+  postconf -e "relayhost=$MAS_RELAY" "smtp_sasl_auth_enable=yes" \
+    "smtp_sasl_password_maps=hash:/etc/postfix/sasl_passwd" \
+    "smtp_sasl_security_options=noanonymous" "smtp_tls_security_level=secure" \
+    "smtp_tls_CApath=/etc/ssl/certs"
+  SMTP_ARG="--smtp 127.0.0.1:25"
+else
+  postconf -e "default_transport=error:5.7.1 outbound mail disabled"
+fi
 cat >> /etc/postfix/master.cf <<CF
 mas       unix  -       n       n       -       -       pipe
   flags=Rq user=mas argv=/usr/local/bin/mas-gateway
@@ -49,9 +71,9 @@ mas       unix  -       n       n       -       -       pipe
 CF
 
 mkdir -p /var/lib/mas && chown mas /var/lib/mas
-# Replies stay in the outbox (no --smtp) until the subdomain has SPF/DKIM.
+# Replies are only recorded in the outbox unless a relay is configured above.
 su -s /bin/sh mas -c "python3 /app/examples/ticket_service/ticket_service.py \
-  --db /var/lib/mas/tickets.sqlite3 --listen 127.0.0.1:8025" &
+  --db /var/lib/mas/tickets.sqlite3 --listen 127.0.0.1:8025 $SMTP_ARG" &
 su -s /bin/sh mas -c "python3 /app/capture.py http://127.0.0.1:8025/mas-events \
   /var/lib/mas/events.jsonl 127.0.0.1" &
 exec postfix start-fg
diff --git a/deploy/railiance/manifests.yaml b/deploy/railiance/manifests.yaml
index 10e58be..c6c13ef 100644
--- a/deploy/railiance/manifests.yaml
+++ b/deploy/railiance/manifests.yaml
@@ -1,6 +1,7 @@
 # MAS live provider test (mail-address-semantics MAS-WP-0003).
 # Founder go for A-D: 2026-10-08. Temporary: delete the namespace after the test.
 # A namespace + MX pod   B LoadBalancer :25   C statute-only ingress   D no outbound mail
+# D superseded 2026-10-18: operator chose replies via Scaleway TEM (Secret mas-relay).
 # IMAGE is replaced with the pushed digest at apply time.
 apiVersion: v1
 kind: Namespace
@@ -34,8 +35,13 @@ spec:
         - name: mx
           image: IMAGE
           args: [mx]
+          # Outbound replies via Scaleway TEM, enabled only when Secret mas-relay
+          # (keys username, password) exists. Port 25 out is blocked on the node.
+          env: [{name: MAS_RELAY, value: "[smtp.tem.scaleway.com]:587"}]
           ports: [{name: smtp, containerPort: 25}]
-          volumeMounts: [{name: evidence, mountPath: /var/lib/mas}]
+          volumeMounts:
+            - {name: evidence, mountPath: /var/lib/mas}
+            - {name: relay, mountPath: /etc/mas-relay, readOnly: true}
           readinessProbe: {tcpSocket: {port: 25}, periodSeconds: 10}
           resources:
             requests: {cpu: 20m, memory: 64Mi}
@@ -43,6 +49,8 @@ spec:
       volumes:
         - name: evidence
           persistentVolumeClaim: {claimName: mas-evidence}
+        - name: relay
+          secret: {secretName: mas-relay, optional: true}
 ---
 apiVersion: v1
 kind: Service
diff --git a/workplans/MAS-WP-0003-provider-live-test.md b/workplans/MAS-WP-0003-provider-live-test.md
index a543ae8..792cf69 100644
--- a/workplans/MAS-WP-0003-provider-live-test.md
+++ b/workplans/MAS-WP-0003-provider-live-test.md
@@ -130,7 +130,17 @@ address and what envelope recipient arrives.
   Consumer Outlook.com runs on the same Exchange Online infrastructure as
   M365, so outbound handling is covered by the two M365 runs. Not covered:
   the Outlook-on-the-web compose form (only the native apps were used).
-  Still open: the reply test (blocked: no outbound mail).
+- Reply test: operator chose to set up outbound now (2026-10-18). Port 25
+  outbound is blocked on railiance01 (to Gmail and Outlook MX it times out;
+  587 and 465 are open), so replies go through Scaleway Transactional
+  Email on [smtp.tem.scaleway.com]:587 with SASL. This is enabled only when
+  Secret `mas-relay` exists; without it, non-local mail fails fast with
+  5.7.1. Image `mas-live:wp0003-20261018b` also runs Postfix unchrooted:
+  the chroot lacked resolv.conf, which is why rDNS showed "unknown".
+  Tested locally against the real TEM endpoint with dummy credentials:
+  TLS verified, SASL rejected as expected.
+  Pending: TEM domain verification and DNS at IONOS (operator), Secret,
+  redeploy, then the reply send.
 
 ## Forwarding and list paths